256GB C300 in MBP C2D 2.66. Still looking good. By all accounts it should be dead or as slow as a snail by now as I've been running it since March and it's nearly full and - shock horror - is still running the original firmware.
Granted, I spent more than originally intended (only bought the 2nd SSD due to a sale earlier this year), but it was worth the space and (to a lesser extent) speed gains.
Then again, dual SSDs are overkill for most users....