In my opinion, I feel it is important to make that game developers understand that to effectivley leverage music, they need to recruit composers who understand both appropriate music forms (not neccessarily classic) and the contexts of game music. If you want professional music, then hire experienced professionals. Furthermore, I feel it is neccessary to involve them as early as appropriate in order to align the soundscape with the overall aesthetic of the game. Don't just tack sound and music on at the end!
I think there are many examples of games that have excellent scores. Many JRPGs by Square-Enix including the Final Fantasy series, Lost Odyssey, Chrono Trigger and other JRPGs such as Xenosaga (Monolith), DotHack (CyberConnect2) and the Metal Gear Solid series (Konami) have a lot to offer. Outside of Japan, there are a variety of games that have wonderful music too. The WestWood's (& EA's) Command & Conquer series immediately jumps to mind, in addition to Blizzard's Diablo series and games such as Bungie's Halo 3 and Bioware's Mass Effect.
Jeremy Soule has been producing music for games for a long time and I am rarely dissapointed. Using Guild Wars as an example, while the gameplay is somewhat different to traditional MMORPGs, the music carries the narritive very effectively. Each region of the game is effectively captured using a variety of styles and moods. Jon Hallur has made some wonderful tracks for EvE Online and released them to the community. Martin O'Donnell's work on Halo and Jack Wall's for Mass Effect - simply incredible. Possibly some of the best examples of orchestral work in games released in the last few years.
In fact, some of my favourite pieces of music in general have featured in popular titles. These include works by Yuki kajiura, Nobuo Uematsu and Yasunori Mitsuda. Three very excellent composers whom, in my opinion, can effectivily exploit music to convey the emotion in a scene or gameplay.