I started playing around Ice Age, and didnt lose interest until the end of Oddesy block. Still have a shoebox or 2 of cards and a dozen+ decks lying around my room. The part I miss was the group we used to have around here - an informal club that met every friday. Wed usually get into large multiplayer games, or split up into groups of 4. The great part about it was that everyone had decks of all types, cards from all sets, and you never knew what would be played next. Plus, multi has a balancing effect since ppl tended to gang up on anyone who got too powerful or annoying. The most fun aspect of the game, IMO, is being able to put decks together just for fun or as an experiment, and trying them out with your friends.
There were a couple guys who were pretty serious about playing in tournaments, mostly standard. Thats the part of the game I couldnt understand, and had no patience for. It seemed like just an exercise in handing money over to Wizards. Download a deck plan from some site, one of the 6 most powerful types that
everyone plays with, buy up all the rares you need, tweak it a little, read up on what to do when facing the other 5 deck types or a mirror match, and youre ready to go. bleh

I agree that many of the older cards were really broken, but Im not sure the newer ones were much better. Morphling, Im looking at you... The other 2 that I recall were the WU 2/2 wizard guy that blocked a named spell from being played, and the 6/6 black/green regenerating guy who gained a +1/+1 counter every time it went into combat. I think the problem with some of these things was that the built-in drawback was too easily overcome (ex. Masticore & Squee). Still a fun game though, most of the time.