Ok, i made a list, prepare yourself:
1) Up Your Arsenal - It has a very similar style to Ratchet and Clank 2, but i chose UYA because of some awesome synthy, trancy, heroic tunes like "Landing Site", "Studio 41" or "Underground Caverns"
2) Deadlocked - This is the game where the developers went dark, and that's reflected in the awesome, evil soundtrack. It's often a mixture of synth and almost metal, for example "Landstalker Stalkin'", "Node Overload" or "Junking The Jammers"
3) Going Commando - Like i said, very similar to UYA, and i just love that style. Favorites include "Flying Lab" (Gotta love that deep saw-bass that comes in at 0:03), "Silver City" (Amazing Stereo) or "Wupash Nebula" (Which is just awesome). It also includes one of my favorites: "The Mine Shaft", because the rhythm and chord progression is just so extraordinary.
4) Tools Of Destruction - This is where good ol' Ratchet and Clank style met the Future series. I really love the Pirate theme. I like the main part of "Pirate Base 2", or "Reencounting Pirates", but i also really like "Cobalia - Spaceport". Oh, and of course "Groovitron 11"..
The problem is, that the soundtrack got a bit boring, either the tunes are very similar, or pretty lame..
5) Into The Nexus - Some amazing songs in there, and the orchestra really was worth it, but it didn't get higher because it kinda lacks the classical Ratchet and Clank OST feel, and because i don't know it that well.
6) Ratchet And Clank - OST was very.. happy back then. It had some remarkable tunes like "Underground Diving", "Scaling The Cliffs" or "Traversing The Fortress", but they all aren't really, "battle music". And if there was battle music, it was no where near GC or UYA.
7) Secret Agent Clank - Yes. The game is pretty crappy, but there are some very cool spy-tunes in the OST, just not many. My few favorites are "Azcotal Alley", "Underground Lab" and the Title Screen. That's also pretty much it..
8) Size Matters - This game was very short, and so there also weren't many tracks, but the ones that were there, were either pretty bad, or pretty good. I don't really like the game, which is probably also why i can't really listen to the OST, because it reminds me of it..
The OST did have some awesome effects in it, and my favorites are "Running Through Mirrors", "Fixing Clank" and "Farming Cooperative".
9) Quest For Booty - I really love the pirate tunes, but a big part of the game is spent wandering around and NOT fighting enemies, which means there is alot of ambient soundtracks, which also means, that there aren't many epic Pirate Battle themes. My favorites include "XMB Music" (This one is simply amazing. It's so calm yet so adventurous), "Battle For The Fulcrum Star" and "Angstrom's Brew Solved" (I know this one is very short, but it has a cool drive to it)
10) A Crack In Time - "Whaat? Why is ACiT so far back? I can't believe it!" Well, first of all (this might shock you), i don't really like this game too much.. it feels too empty, not replayable and just way too cinematic. I don't have a problem with storytelling or anything, but the action really is reduced in this game. And so is the musical action. It's very "sinewave-ish". and there are no really remarkable, innovative and exciting tunes. Most of it is either percussion or that typical "DAMM DADADA DAMM" stuff. Also, i don't really like the main theme in this game, which obviously explains why i don't like most of the songs. AND THERE'S ALMOST NO SYNTH that was what MADE Ratchet and Clank for me.. Well yea.. here are some i still like: "Chasing Down Azimuth", "Fixing Anomalies" (Calm but pretty cool actually), "The Outer Islands" (pretty creepy, and i like it), and of course, the Groovitrons
My absolute favorite track though, is the unused track. That was awesome to the max (except for the voices..), and i have no idea why they cut it..
11) All 4 One - Well yea.. maybe it's because the huge cluster of beeping and low-quality explosion sounds were louder than the music, but literally NO track is stuck in my head, except maybe the main theme, which wasn't that bad actually.
12) Full Frontal Assault - meh..
So, now my head hurts as well as my fingers, and probably your eyes, but that's it.