Just a couple of months ago I played through THPS1 and 2 on my DC, just one skater but 100% for him (can't remember which one). I had forgotten how freaking amazing these games were.
Then I borrowed THPS3 for the PS2 from a friend, played it for maybe an hour...and gave it back. Pretty much everything from THPS3 on I couldn't stand. The moon physics bugged me, the levels were less interesting, and it just seemed so much slower and less interesting.