Sehsuan, I think what you're looking for is Miranda (Windoze).
For the original poster: VLC is very useful. It not only lets you open and view videos encoded in most of the codecs, it also will allow you to bypass the region limitation of the DVD player. No longer will you have to switch regions to play DVDs from somewhere else. Also don't have to flash firmware or do anything to your hardware. Just use VLC, and open disc from there.
I don't believe Skype's video chat is of better quality than iChat. iChat is the best that I've seen, and also the most features (>3 party conference). Skype's video features are still in beta. Best used with iChat for >2 macs and every party using iSight cameras. Probably what you friend means is that when doing cross platform conferencing with you, it's better quality than him using iChat, and you using AOL IM.
Other useful software. Let me see.
Quicksilver. (Indispensable. Application launcher + productivity tool; i.e. can do things like email, move files, append text, with a few strokes of the keyboard)
Burn (advanced disc burning software, as good as the expensive Toast software)
CoconutBattery
Journler
Gleam (for flickr upload)
WriteRoom (for writers... full screen writing in 'dark room like' environment. distraction free. helps writers like me get things done.)
I use sites like the following to discover new software:
http://coolosxapps.net/
http://osx.iusethis.com/