I thought KimiKiss had a good OST. I have it and I’ve listened to it several times, though only a handful of tracks stand out as having stand-alone listening value. A lot of the tracks (Hashimoto does this too I think) use the same exact infamousized-in-the-40’s-doowop progression, I-vi-ii-V, which is pleasant but can get a little boring unless the arranger does a great job of making you listen to more than just the harmony.

It’s probably unfair of me to judge an OST by how much of it I remember, but that could also be due to the anime. At any rate, I don’t have a desire to go back and listen to TM8.0’s stuff :/.

A few of the others though:
Kimikiss: nice enough, though I’ll be damned if I can actually remember any melodies. That series kept the soundtrack in the background and it didn’t strike me as being memorable. Caveat is that I’ve only listened through the soundtrack once and it’s nice, but non-descript (I need to give it a more thorough listen).
Toradora: non-descript and just not all that captivating. I fell asleep halfway through the album and needless to say, I’m not convinced of Hashimoto’s musical talents as of yet. In my mind, much worse than Kimikiss. At least Kimikiss never bored me :\
Anything that I didn’t comment on I never listened to. Those might have a fighting chance if all goes well.

Hayate: never listened, no comment
Shana: It’s like Kou Otani he takes the more intense tracks from Shadows of the Colossus and sticks them in here. The result is good, but not great. I enjoyed it though.
Index: Far too much electronica. You already know I’m not a fan of I’ve Sound’s composers. Guess the group that Index’s composer belongs to?
Nodame: Terrible terrible terrible. For a classical-music-themed anime series, the soundtrack was lackluster.

As for the others:
TM8.0: This might fall into the non-descript-but-pleasant melodies section. I’ll have a better clue if/when I listen to the soundtrack.
Bakemonogatari: Sometimes my expectations will not correspond to reality. This might be good, but my impression based on the anime is that it’s unremarkable. Will test to see whether his music is decent.

IIRC TM8.0 music sucked balls. I don’t remember anything.

Bakemonogatari had some…interesting music. Clearly, Kousaki was having a hell of a lot of fun with this. Some tracks are vaguely stylistically reminiscent of the fun, goofy and noodling-around-y tracks in Lucky Star. There are also some more complex and interesting tunes, I’m thinking of the jazzy one in ep11(?) when Araragi is talking to Hanekawa about, like, her father beating her or something…

Although having said that I need to correct a brain fart… Bakemonogatari’s OST Volume 1 will be out 27 January next year with DVD volume 5. Volume 2 should follow a month later with the next DVD, I predict.

Also, with regards to Hattori’s work, his drama compositions are a joy to listen to, and he’s far more prolific in that field. Until a while ago he was the one of the go-to composers for big budget shows…the Nodame drama adaptation included.

(In Bakemonogatari’s case the DVD will come December… I forgot the exact day)

No idea when the Bakemonogatari OST will be out, so I’ll have to wait and see.