Y!M 8
With the latest version of Yahoo! Messenger 8 beta, Yahoo has once again proved they have most innovative and useful ideas about instant messaging. Major feature of this release as already reported on so many other sites is third party plug-ins. Just to give one example, I installed amazon's plug-in and now I can see amazon wish-list of all 150 contacts of mine just by selecting their name. Such a time saver when buying gift for someone. I do not know any other messenger that comes close to Y!M in terms of useful features, stealth settings, offline messages, VOIP, .. all in one. I have been using Windows Live Messenger 8 Beta as well but Yahoo just beats everything.
Most of my friends use Trilliansince that saves you time from using 4-5 different IM provides like Yahoo, MSN, AIM etc. But then you can't use specific features of any one provider. It would be really nice if I can use all my accounts like AIM, MSN from Yahoo Messenger. Is that too much to ask? 
Update: Actually MSN Live is working on interoperability with Y!M. Will Yahoo follow same?
