1997. I could write a huge essay on exactly why this season was so good. There were so many brilliant races, lots of unpredictability and a highly competitive grid - you could argue that every race was very good, or at least highly watchable. A couple of the reasons why i think this is the best and most memorable season since i've been watching:
- Panis' early season giant killing (which was cruelly halted)
- Hill's near victory in a very shoddy Arrows
- Berger's excellent final victory
- A resurgent McLaren leading 1-2 at the Nurburgring, only to bizarrely have their engines blow in the exact same spot one lap apart
This all led to that showdown at Jerez, for me one of the best (if not the best) title showdown races there has been.
1995 would go on this list for me as well. Another action packed season, highlights including that insane race at Monza, and Damon Hill winning by over 2 laps in the highly attritive final race at Adelaide. Oh, and a certain Frenchman driving a certain number 27 car

The final season is a tough call between '05, '08 and 1994 (despite the tragedy of that season).
Hmm... i'd probably say 2005 edges it for me. For starters, it was such a relief to see an end to the most predictable and boring period of F1 history. The tyre rules that season, although slightly crazy, did create a hell of a lot of great races and incidents - i'd perhaps even say again that almost every race was watchable. Obviously USA isn't included there...!
The best season that i don't class myself as having experienced firsthand? I'd have to go with 1982, again, despite the tragedy that struck that season.
The worst season ever was 2002, hands down. The biggest letdown was 2009, there were far too many nondescript races after all the hype. Ah well.