Here's an update. This is my current complete list (of those I've noticed on my site - you may have others, so be careful):
Code
Alexa=ia_archiver
Altavista=Scooter      
AllTheWeb=FAST-WebCrawler
Excite=ArchitextSpider
Google=Googlebot
Yahoo=Yahoo! Slurp
Inktomi=Slurp
MSN=MSNBOT
Whois.sc=SurveyBot
Google-AdSense=Mediapartners-Google
TAMU.edu=IRLbot
InfoSeek=UltraSeek
InfoSeek=InfoSeek Sidewinder
Lycos=Lycos_Spider_(T-Rex)
ScrubTheWeb=Scrubby
Looksmart=MantraAgent
SingingFish=asterias
Ask.com=teoma_agent1
Voila=Voila
AskJeeves=AskJeeves
Voyager=Voyager
Voila=Voila
SnapPreviewBot=SnapPreviewBot
Snapbot=Snapbot
BoardReader=BoardReader
YodaoBot=YodaoBot
TMCrawler=TMCrawler
StackRambler(ru)=StackRambler
EntireWeb.com=Speedy Spider
Gigablast Gigabot=Gigabot
Twiceler (leech?)=Twiceler
NaverBot=NaverBot
BecomeBot=BecomeBot
MJ12bot=MJ12bot

Replace Control Panel » Display Options » Who's Online » Search Engine Agents with that list (unless yours contains some not mentioned here; if so, post them wink )

Hopefully these extended lists will end up in a default/updated version of a future UBB release... wink

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