Is this drive fast enough for a modern PC?

No. It is a 5,400-class 3.5-inch drive with an 8MB cache and SATA 3Gb/s, so it is far slower than current hard drives and SSDs. Use it for a replacement or light storage, not as a boot drive for a new build.

Will it work in my DVR or set-top box?

Likely yes if the device takes a 3.5-inch SATA drive. The Pipeline HD line was made for consumer electronics, so it runs quietly and draws little power. Check your device's capacity limit, since some older boxes cap drive size.

How much can I actually store on 160GB?

Roughly 150GB after formatting. That is about 30 hours of standard-definition video or tens of thousands of photos, but only a few modern games or a modest music library.

Does it need a special cable or power connector?

It uses a standard SATA data cable and a SATA power connector from the power supply. No adapter is needed in a desktop with free SATA ports.

Is it a good choice over a larger drive?

Only if you need a like-for-like replacement or a quiet low-power disk for old equipment. For general storage, a larger current drive or an SSD gives much more room and speed.