.hack/Infection series-- I ate slept drank and dreamed about this game for abut 2 months, playing it every time i was near a console [eg any time i wasn't at my own place].
The graphics were gorgeous, the plot was entrancing, the combat was actually fun and not totally tedious and intrusive as in eg FF games [not that i haven't tried or wanted to play them, but aside from ff7 once, i really truly cannot get over the random encounters and always just quit].
Probably the best description is it is a single-player mmorpg, different main cities with their own shops and big 'player' population.
It has lots of diffferent zones with a keyword system to determine where you go and the sort of environment [eg Radiant Octahedral Teaspoon might take you to a level 30 marsh zone or summat]. Almost all of the other 'players' have items for trade, eg for 20 holy saps they'll trade a Magic Tab or suchlike, or more common ones that just will trade x value of stuff for y. Moreover scattered throughout the zones are magic pools into which you can throw weapons or armour to upgrade them based upon weather conditions and daytime/nighttime and such.
There is a whole desktop/os thing designed for it as well, including a mail client to keep in contact with different 'players', particularly recurrant party members, and gain information about things, and a fairly active and informative bulletin board, and a local news ticker and such.
It was incredibly fun, however i think i burnt myself out from playing too much too quickly, and a good bit of the way through the first game of four [you can keep your character as you go along], and i haven't even looked at it in months. [though i have thoroughly enjoyed watching .hack/sign instead].
The whole sp mmorpg really, was imo brilliant [at first at least], because most of my complaints about multiplayer gaming involve the fact that it involves other people [who just a few of which can utterly wreck it, or just human nature bleeds through the economy or sociology so much that it just is totally bothersome]. I am, for instance, utterly in accord with this pvp strip [mild language i think]:
http://dor.nullmind.org/arc/pa-20040216l-robotworld.jpg
Other than that, i've never really been much of a console gamer. Mostly just things like secret of mana and it's sequels, or zeldas, or of course chrono trigger.
However, i did quite enjoy playing through bits of Prince of Persia, and Prince of Persia 2 is gorgeously sexy, though i mostly just died repeatedly during the first boss encounter even on easy, so i've been having fun back-seat-playing it with my friend instead.. "Turn that crank! Pull that lever! Dodge dodge dodge!"
Also, I can kill you with my brain.