A snippet from my .htaccess file to list the blocked bots:
RewriteCond %{HTTP_USER_AGENT} ^BlackWidow [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Bolt\ 0 [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Bot\ mailto:craftbot\@yahoo\.com [NC,OR] RewriteCond %{HTTP_USER_AGENT} CazoodleBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^ChinaClaw [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Custo [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Default\ Browser\ 0 [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^DIIbot [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^DISCo [NC,OR] RewriteCond %{HTTP_USER_AGENT} discobot [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Download\ Demon [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^eCatch [NC,OR] RewriteCond %{HTTP_USER_AGENT} ecxi [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^EirGrabber [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^EmailCollector [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^EmailSiphon [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^EmailWolf [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Express\ WebPictures [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^ExtractorPro [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^EyeNetIE [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^FlashGet [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^GetRight [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^GetWeb! [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Go!Zilla [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Go-Ahead-Got-It [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^GrabNet [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Grafula [NC,OR] RewriteCond %{HTTP_USER_AGENT} GT::WWW [NC,OR] RewriteCond %{HTTP_USER_AGENT} heritrix [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^HMView [NC,OR] RewriteCond %{HTTP_USER_AGENT} HTTP::Lite [NC,OR] RewriteCond %{HTTP_USER_AGENT} HTTrack [NC,OR] RewriteCond %{HTTP_USER_AGENT} ia_archiver [NC,OR] RewriteCond %{HTTP_USER_AGENT} IDBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} id-search [NC,OR] RewriteCond %{HTTP_USER_AGENT} id-search\.org [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Image\ Stripper [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Image\ Sucker [NC,OR] RewriteCond %{HTTP_USER_AGENT} Indy\ Library [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^InterGET [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Internet\ Ninja [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^InternetSeer\.com [NC,OR] RewriteCond %{HTTP_USER_AGENT} IRLbot [NC,OR] RewriteCond %{HTTP_USER_AGENT} ISC\ Systems\ iRc\ Search\ 2\.1 [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Java [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^JetCar [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^JOC\ Web\ Spider [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^larbin [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^LeechFTP [NC,OR] RewriteCond %{HTTP_USER_AGENT} libwww [NC,OR] RewriteCond %{HTTP_USER_AGENT} libwww-perl [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Link [NC,OR] RewriteCond %{HTTP_USER_AGENT} LinksManager.com_bot [NC,OR] RewriteCond %{HTTP_USER_AGENT} linkwalker [NC,OR] RewriteCond %{HTTP_USER_AGENT} lwp-trivial [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Mass\ Downloader [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Maxthon$ [NC,OR] RewriteCond %{HTTP_USER_AGENT} MFC_Tear_Sample [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^microsoft\.url [NC,OR] RewriteCond %{HTTP_USER_AGENT} Microsoft\ URL\ Control [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^MIDown\ tool [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Mister\ PiX [NC,OR] RewriteCond %{HTTP_USER_AGENT} Missigua\ Locator [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Mozilla\.*Indy [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Mozilla\.*NEWT [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^MSFrontPage [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Navroad [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^NearSite [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^NetAnts [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^NetSpider [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Net\ Vampire [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^NetZIP [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Nutch [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Octopus [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Offline\ Explorer [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Offline\ Navigator [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^PageGrabber [NC,OR] RewriteCond %{HTTP_USER_AGENT} panscient.com [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Papa\ Foto [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^pavuk [NC,OR] RewriteCond %{HTTP_USER_AGENT} PECL::HTTP [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^PeoplePal [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^pcBrowser [NC,OR] RewriteCond %{HTTP_USER_AGENT} PHPCrawl [NC,OR] RewriteCond %{HTTP_USER_AGENT} PleaseCrawl [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^psbot [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^RealDownload [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^ReGet [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Rippers\ 0 [NC,OR] RewriteCond %{HTTP_USER_AGENT} SBIder [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^SeaMonkey$ [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^sitecheck\.internetseer\.com [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^SiteSnagger [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^SmartDownload [NC,OR] RewriteCond %{HTTP_USER_AGENT} Snoopy [NC,OR] RewriteCond %{HTTP_USER_AGENT} Steeler [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^SuperBot [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^SuperHTTP [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Surfbot [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^tAkeOut [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Teleport\ Pro [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Toata\ dragostea\ mea\ pentru\ diavola [NC,OR] RewriteCond %{HTTP_USER_AGENT} URI::Fetch [NC,OR] RewriteCond %{HTTP_USER_AGENT} urllib [NC,OR] RewriteCond %{HTTP_USER_AGENT} User-Agent [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^VoidEYE [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Web\ Image\ Collector [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Web\ Sucker [NC,OR] RewriteCond %{HTTP_USER_AGENT} Web\ Sucker [NC,OR] RewriteCond %{HTTP_USER_AGENT} webalta [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebAuto [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^[Ww]eb[Bb]andit [NC,OR] RewriteCond %{HTTP_USER_AGENT} WebCollage [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebCopier [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebFetch [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebGo\ IS [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebLeacher [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebReaper [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebSauger [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Website\ eXtractor [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Website\ Quester [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebStripper [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebWhacker [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WebZIP [NC,OR] RewriteCond %{HTTP_USER_AGENT} Wells\ Search\ II [NC,OR] RewriteCond %{HTTP_USER_AGENT} WEP\ Search [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Wget [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Widow [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WWW-Mechanize [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^WWWOFFLE [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Xaldon\ WebSpider [NC,OR] RewriteCond %{HTTP_USER_AGENT} zermelo [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Zeus [NC,OR] RewriteCond %{HTTP_USER_AGENT} ^Zeus\.*Webster [NC,OR] RewriteCond %{HTTP_USER_AGENT} ZyBorg [NC,OR] RewriteCond %{HTTP_USER_AGENT} JSimplepieFactory [NC] RewriteRule ^.* - [F,L]