I've played through MGS 1-3 in anticipation of MGS4. Haven't started up 4 yet, as there was a family emergency last week and I'm moving this week, but I thought I would christen the review forum with my thoughts on the first 3 -

MGS1 - Great game overall. Bad graphics didn't really bother me as much as I thought they would, and it was surprisingly easy to target enemies. Wasn't a huge fan of the backtracking. Storyline was great, and the bosses were awesome, though I had seen most of them back when the game originally came out (even though I didn't play the game until now) so there weren't really any surprises.

MGS2 - First impression was that the controls were so terrible I quit after an hour and a half and didn't come back to it for a month. Glad I gave it a second chance, because the game is actually pretty good. I kind of liked the concept of the whole game (plant chapter, anyway) taking place in that one facility. As is the standard response, I thought the story just got too carried away at the end; if they had spread all those cutscenes out over another couple of hours of gameplay, it would have been better, but there was just WAY too much watching and flipping revelations that were had 10 minutes ago. Bosses were a little weak imo.

MGS3 - Started off WAY too campy, what with stupid jokes about movies coming out in the future,
Spoiler
etc. Game definitely picked up later, though. The bosses were excellent, and once it picked up after the slow beginning the story was pretty good. The ending was AWESOME. Boss battles were very cool, particularly The End.

I'm very much looking forward to playing MGS4 once we get settled in the new house. Planning on taking no longer than a week to beat it, so I'll update the thread with my impressions once I do.