Indie games in general have great OSTs, MGS:R and Persona (and SMT in general) are obvious popular picks.

The World Ends With You is less mainstream (with one of the few gripes being the lack of boss-specific themes, at least in the DS original I played - but it makes up with the diverse overworld and normal battle themes), as is Etrian Odyssey.

I think orchestra is mixed, it's either the best fucking tracks ever (often when mixed with electric guitar, but not necessarily), or they kind of blend with other orchestral tracks I know and don't end up being unique enough.