I play trumpet as well...My advice is stick with the jazz. Improvisation is as much about practice as anything else, really, and it's definitely one of the things I'm grateful to have learned. Being able to sit down and play with a bunch of random people and connect musically through largely spontaneous music is a pretty fucking great feeling, not to mention the freedom of expression it brings over classical.
As for recommendations- Inlander will no doubt inundate this thread with quality jazz-trumpet recommendations.
Until then, you might try starting with one of the most influential trumpet players of all time, one Miles Dewey Davis. This guy seriously wrote the book on a number of genres, and was a huge influence on other jazz greats, like Coltrane, John McLaughlin (one of my favourite guitarists), Herbie Hancock, just to name a few. I'd recommend starting with recordings from his first big quintet, or the second, as the be-bop stuff and/or the fusion stuff might be a little more difficult to get into (but you definitely should check it out as well).
Apart from Miles, check out Bix Beiderbecke, maybe, as far as jazz goes. Also that trumpet player from Duke Ellington's band, who was all about the flutter-tongue and wah-mute. Can't remember his name off-hand though, I'll have to look it up, but he's one of my favourite players using that style.
If you want to hear some interesting contemporary stuff, check out Nils Petter Molvær's
Khmer. Nils has a very distinct, breathy tone which he combines with a number of electronic effects and production to create some hauntingly beautiful music.
Edit: Forgot one of my New Favourite Bands:
Hypnotic Brass Ensemble. These guys are seriously the best thing ever.
