Unfortunately, I think that SqueezeCenter (now Logitech Media Server) is the only server that gets the browsing right, although it's more difficult to use as a phone based roving music collection than Subsonic. It allows both folder and tag based browsing, with tag based browsing allowing following the path from: genre -> artist -> album -> song (or play all at any/each of those levels). It also handles multiple tagging ("Classical;Opera" = "Classical" + "Opera", for example). If those 2 features were added, I would throw away all of my other music players. I have a large and eclectic music collection, so this may be less important for others, but I have and use:
Subsonic - convenient, but only folder based and multiple tags not handled
SqueezePlayer/Squeeze Commander - not as convenient to set up to play, but otherwise tags & browses from server
PowerMP - general purpose local music player; handles multiple tags, but can't browse from "genre" -> "artist" -> "album"
MixZing - decent local music player; can browse genre -> artist -> album almost well, but doesn't handle multiple tags
Google Music - can hold a large collection and stream for free, but can't hold my entire music collection; can't browse genre -> artist -> album; and doesn't handle multiple tags
Amazon MP3 - not very convenient, but can stream Amazon MP3 purchases; doesn't even handle "genre"
V. A. M. P. - reasonably good voice searched local player
Both my folders and my tags are well organized, so folder vs. tags isn't about being lazy regarding keeping both organized. It *is* about information in tags that doesn't fall within a straight forward folder structure... multiple genres per artist, per album, or multiple artists per song, etc. It's odd that Subsonic, for all it's other sophistication, doesn't deal with tags for browsing, only searching.