ive got an athlon 2500 barton 512mb @169fsb, running nearly 24/7, sometimes used for gaming.
athlon 1500-mobile 320mb, running 24/7 not used, just surfing net.
and my g/f's celeron 2ghz 240mb, running nearly 24/7 at the mo, but its usaully just on when getting used.
ive got an old amd k6-2 500, 256mb that i gave to my gran and grandad i could put it on too,
and my g/f old via 533, but it doesnt have net access. her bro uses it now.