PSP: Yeah, I haven't found a good cheap image editor for MacOS. Personally, I really liked Paint.NET for Windows, but I think your best option under MacOS is The Gimp, which ... well ... yeah.

pyTivo: Yeah. It'll work under MacOS. Better than under Windows. MacOS comes with the Python interpreter.

uTorrent: Yeah, uTorrent really is the best torrent client available. Transmission is a pretty good torrent client. As long as you want to download all the files in the torrent. If you don't, it'll waste hard drive space when it writes three bytes to files you don't want and allocate all the rest of the space for that file. You can use Azureus, too. It's still a good client. As long as you don't mind your computer running at the speed of a TI 99/4A.

Openoffice.org: NeoOffice. You can also run the X-Windows version of OO.o, but I don't see any reason you'd want to do that.

GMail Notifier: Google Notifier