i heard the 808 and the 909 are good. j/k.
on the computer front, reason is awesome. there's this program called battery, but i think it might be mac only, but computer music mag gave it a top rating...
hardware wise, the zoom drum machines actually sound pretty cool to me. i've had 3. the rhythmtrak 123 is the one that was really good.
boss/roland make good drum machines too, but i'd prefer making beats with a good program like reason