Most of my vinyl is your bog standard 120 gram stuff, bought cheap second hand from record shops etc. As said above, if its a good recording it will sound good on 120 or 200 gram.
For records i realy, realy like, ill stretch to the 200 gram super duper re pressings, ie i have most the classic records led zepplin releases, dark side of the moon on 180 gram etc, they make lovely collector type items too, usualy with realy nice heavy card sleeves etc.
www.acousticsounds.com is a good source for such things, they even shipped to the uk for me
edd