Do you have a list of good module (MOD, S3M, IT, XM) music you can recommend for me which I can use in my levels? Or just give some inspiration?
Here are my recommends:
Jazz Jackrabbit 1, 2, 3D Soundtracks (of course)
Remixes and related tracks of above
Elwood's music (15 XMs)
D Fast's music (8 XMs - so far)
Rapture's music (27 XMs)
Superfrog MODs (I have 10 MODs & 1 XM)
ingame.IT ("Pocket Tanks (ingame)")
pocket.IT ("Pocket Tanks (intro)")
Swingveg.it ("Swing Your Veggies")
7thheaven.mod ("7th heaven")
BeatWave.mod ("beatWave")
bladerav.mod ("bladeraver")
bubble.mod ("the funky bubble")
Lemmings.mod ("LEMMINGS")
Pacman.mod ("Pacman (game theme)")
Seasons.mod ("Seasons")
Cosmic.xm ("cosmic outflow")
dukerave.xm ("Da Duke 3D Rave")
nukem3d.xm ("Techno Duke")
odetoduke.xm (". Ode to Duke .")
scworld.xm ("scatman")
Sunflower.XM ("sunflower.game")
T.XM ("Terminated")
tyrian1.xm ("Tyrian, The Level")

I have too many to list them all, but these enquired my attention.

Those all suck, excluding Swing Your Veggies.

Approach.it (Approach)
last-nwk.xm (Last Sunset)
Gw2.it (Gateways part 2)

whitecoffee.xm (you can find it in Martin's 5 Alive pack)