Standard SATA data cable and a SATA power adapter unless the drive also has a standard power connedtor (or your PSU already has them - some mobos come with at least one SATA data and power adapter cable - the Abit KW7 I just got had two data but no power adapter cables). You'll find a mix of power connectors on drives, some have only the SATA connector, some have the old style Molex and some have both.
.bh.
.p.s. some SATA data cables have a latch that locks them to the drive. The ones I've seen are considerably more expensive but help prevent accidental disconnections/breakage by the ham-fisted. Breakage seems to be fairly common judging from the posts here...
.bh.