The real answer depends on what your use for the TV card will be and the rest of your system. I've personally had several AIW cards, including my present AIW 9700pro. I've not had to reformat a single time I can remember just for a driver change, and CPU use at the highest settings are ~45% for MPEG-2, however just watching TV is under 10%. I also use hardware eHome Wonder cards with SageTV (soon to be MCE 2005). Its the opposite from the AIW in that recording uses low cpu, however watching is higher than the AIW.
Short answer (well, shorter than it could be):
General TV Watching: AIW card. Its hard to beat an AIW 9800pro for ease of use, and it's a complete package. Native YPbPR output if you have a compatable display is a great feature as well. If you upgrade your graphics often, it "may" not be your best bet. However, the also retain there value longer and are quite useful even when gaming performance can't hack the newest games.
Real PVR duties: A hardware encoder TV card is excellent for PVR duties. Scheduled recordings work better, as do background recordings. They work well on much less powerful rigs, and can transfer over to your new rig when you upgrade. They do generally have poor software unless you get a bundled deal. They do support the popular 3rd party softwares like BTV and SageTV ( I use SageTV, and its pretty good software package) and also XP Media Center. I use eHome Wonder cards, hauppage PVR cards are supported in more softwares.
Gamer watches some TV already has a good graphic card: One of the lessor expensive software encoder cards like the leadtek or Asus cards. They offer good performance at an inexpensive pricepoint.
Other considerations: I'd forget the ATI TV Wonder cards, there are just too many issues for me to recommend one.
I do use an HDTV Wonder, and its a decent card that I can recommend, but needs some software polish. Even the analog tuner works well, and I haven't experienced the issues that plague TV Wonder users. ATI's new TV Wonder USB2.0 looks like a winner, but isn't available yet (great for a notebook, or any PC w/USB 2.0 port) The new cards that will feature the Theater 550 chip from ATI aslo look like winners, but again, not yet available
Edit: I just noticed TV Wonder USB 2.0 is available through shopATI and Newegg.