meh... i played Doom shareware (and i had it for the GBA) and i just thought it was shit. i can understand how it would have been great when it was released, but it was so depressingly grim that it made me want to cry. Doom3 makes you cry, but in a different way... when there are 5 imps pounding you through the corridoors, and a number of hellish creatures cut you off and start pounding you with annoyingly firey attacks and sounds before you go phycologically insane.
I played Doom again to get me hyped for Doom 3 - and enjoyed it greatly. Unfortunately Doom 3 didn't impress, and reaked of mediocrity (imo).
The original all the way (just think how much fun Doom was the first time you played it Doom 3 can't compare to that. Hell, it has trouble comparing to many 100's of games)
i liked doom3 but i love classic doom. classic doom was so gritty. thats the only word i can think of to explain it. it made you feel dirty after you played it for too long, as if you were a bad person.
i love it
edit: now i feel dirty just thinking about playing doom2...