Get the ATI USB 2.0 tuner. It lets you run the last version of ATI MMC software that actually worked (9.08). The software Mpeg encoder can go up to 15Mbs for virtually lossless captures of tape. Tape is hard to encode at lower bitrates because of noise and jitter.
The software mpeg encoder also has a "pause" button on the UI which is extremely handy to edit on-the-fly during a capture. Shame on ATI and all other vendors for dropping a feature that consumer VCR's had in 1978!
For HDTV, get the Dvico Fusion USB tuner. Again, it has a great tuner app.
There is no need to open up a system and lose PCI slots when USB runs at 480 Mbs.
Note that a plain old "video capture card" will not allow you to watch live over-the-air TV on your PC. You need a card that has a TV tuner on it. Moreover, most TV tuner cards also do video capture, but not all of them. So, be circumspect when checking out various TV tuner brands. Look for a "svideo in" or "analog composite in" port on the card.
For example, Dvico makes the Fusion 5 Gold GT and the Fusion 5 Lite. The Gold includes a separate svideo port for video capture from external video sources like a VCR, camcorder, game console, or DVD player. The Fusion Gold Lite does not have a separate analog video capture port. Both cards are combo analog/digital HD tuners, however.
If you are using a plain Windows XP box, then most of the name brand TV cards with video capture will do what you want, record from the satelite. However, some software and/or tuner cards prevent you from recording encrypted satelite programs from sources like HBO. Most will allow recording non-premium/unencrypted TV like ESPN.
Windows Media Center does not allow recording encrypted satelite from within WMCE. However, WMCE will set up a satelite feed so that you can use WMCE remote control to do channel changing on the satelite STB.
As for recording VHS tapes to your PC hard drive, most plain old video capture cards can do this just fine. It is usually a strait forward process of connecting the VCR video out to the video in on the PC, and using software for the recording. Windows Movie Maker can do this. As I suggested, a TV tuner card with an analog capture port can also do this.
The best way to record VHS tapes to the hard drive is to use a miniDV camcorder as the intermediary device to convert the analog video from the VHS tape to digital video, which makes for lossless recording on the PC hard drive. There is virtually no loss in video quality during the conversion. Make sure that the miniDV camcorder has a "A/V in" port as well as "A/V out" ports. Many brands of miniDV camcorders only have "A/V out", allowing no way to get your VCR analog out connected to the camcorder. Lastly, the miniDV camcorder must have a 1394/iLink/Firewire port with which to connect to the computer.