pzler: The Interface speed of Mac OS 9 should feel much snappier than OS X. The drawback is that multitasking is not as refined. If it takes 30 seconds for Photoshop to launch, you have to wait the full 30 seconds in 9. In X, you can switch to another program while Photoshop launches in the background.
If you have older versions of apps that coincide with OS 9, then they should run just fine. It seems like each new version of Photoshop or MS-Word gets slower and slower - requiring a faster computer to do the same old tasks.
Mozilla 1.3.1 (an unofficial release) runs rather well on Mac OS 9, and is newer than Netscape 7. I recommend iCab 3.0.3 as it works well, is fast, and has some nifty features.
Sludgedragon: I have a Wallstreet with a WaveLAN Gold WiFi card. The card worked just fine with Apple's AirPort driver in 9.2. I too looked into the commercial drivers for OS X, but ended up finding a free driver at SourceForge. The description mentioned Jaguar, but it seems to work just fine in Panther. Of course, it isn't nearly as refined as Apple's drivers, but it is FREE.
tomlee: Older versions of iMovie work surprisingly well on older, slower computers running OS 9. I had to use iMovie on a 120MHz PowerMac 8500 once. It captured the video from my MiniDV camcorder just fine, where Premiere 6 on my 9600 (with 700MHz G4 card) would drop frames during capture. I ended up doing the project in Premiere, but then exporting back to tape from iMovie on the 8500.