Ahh, I'm just your guy.
First, off, yes, VIVO = Video In/Video Out. One serious issue with some setups that have video in on the display adapter and require audio input from the soundcard is that sometimes the audio and video will get out of sync after a short period of time when capturing. Viewing is another story, but capturing can be pretty stressful on a system. Your 7200RPM harddisk *should* be ok and your CPU might cut it as well. Though, a lot of that will depend on the capture device you end up purchasing as well as the codecs/filters used in real-time.
I have not been satisfied with the quality from the low-end Hauppauge cards. Though, I have tried the WinTV-PVR-350 and it was ok, though I found the software to be clunky/slow. I have not tried anything from Pinnacle, though, I have read nothing but bad reports about driver issues with their cards. I don't think I could recommend them and keep a clean conscience.
Right now I have an ATi All-In-Wonder Radeon 9700 Pro. It's ok, but I'm far from satisifed with the quality it produces. Though, it's great for watching full-screen TV or for sending a pass-through signal to the monitor for viewing full screen. I also run a Canopus DV Storm2 for my main capturing. It's the best capture/editing card I've used to date. It costs an arm and a leg, but it's well-worth the cash. I can record for hours and hours without any dropped frames. Applying filters in Premiere is a snap, no hassles and it's fast as the wind.
I also run a Canopus ADVC-100 on my Macs. Like the DV Storm2, it can record forever without any dropped frames. Now this is simply an analogue to digital converter that communicates via FireWire so it simply feeds the analogue streams to the computer. There's really no stress on the computer at all. I've done a lot of capturing on slower machines all the way down to my iMac G3 700MHz.
A few pointers you should keep in mind are that you want one device that handles both your audio and video. This will help reduce, and hopefully eliminate any possibility for any A/V sync issues. Also, close as many programs as you can when capturing to avoid them interfering with the system or tasking the harddisk while capturing to prevent dropped frames. Lastly, disable your antivirus when capturing.
Good luck.