Cool! I'll definitely be saving this list for later. What do each of these objects do? I assume VLC media player plays media, by which I mean DVDs? What's the iStat widget and the Omni suite? Will these be available in the App Store?
VLC plays DVDs, but also movie files. It's good to have on the off chance of needing to watch a movie that Quicktime doesn't play, or if you want to make movie playlists. I've also experienced that it would play obscure DVDs with interaction on them that Apple's player didn't understand. Even though the DVD image quality is supposedly better in Apple's player, VLC doesn't respect "unskippable" DVD content, so you can skip the FBI warnings in Czech if you want. Incidentally, the mentioned Perian extension to Quicktime is the core of VLC compiled to a bunch of codecs, which will enable Quicktime to play more content if you prefer that.
iStat is a Dashboard Widget, meaning mini-application that keeps track of every aspect of your Mac, like processor load, temperature, fan speed, disk usage, network and battery. It's just nifty as well as useful.
Omni were some of the first developers outside of Apple to really get the Mac UI thinking right. They have a range of productivity applications for task lists, Gantt diagrams, graphs, flowcharts and - oddly - David Allen's Getting Things Done. I ended up paying them for their task list software after searching far and wide for a free alternative, and haven't regretted it. Like the Mac experience overall, this software just has a level of polish that has saved me many hours since.
The Omni group have their software on the app store, but the VLC stuff are open source projects you'll have to google. They do have easy installers, though.
I just remembered that I use Colloquy, which is also free, for IRC chat, and Firefox's FireFTP extension for FTP. Forgot to mention it, but what CleanArchiver does is make zipped archives to send to Windows users. Apple's own zip tool includes some Mac-specific hidden files that show up on Windows and can be confusing.
Whew. I've been thinking of compiling this stuff somewhere, but there are good sites for beginners already, like Macrumors.com. Again, good luck.