Hey charlie,
May I ask what source you are using, and which genres you like?
For musical enjoyment, two great IEMs are the Sennheiser IE80 ($270 from amazon.de) and the Klipsch X10. Around Black Friday the X10 was selling for 84.95 which is great value. Now they're about 116, but the price probably fluctuates, so don't rush.
I also have the Klipsch S4, and I find the X10 to be a significant step up from them in terms of soundstaging, detail reproduction and bass control (the S4 is a little loose in the bass, and can get sibilant, but it does sound better than many other IEMs you find on store shelves).
The IE80 is one of my favourite IEMs - its sound is relaxing and easy to enjoy. At $270 (much cheaper than its too-high MSRP of $450), it is again another step up from the X10s, with an unusually wide soundstage, superior resolution and great mids. The bass provides both quality and quantity to my ears. In any case, bass is adjustable via a dial on the side of each earpiece, and at the minimum level it's not overpowering at all IMO (perhaps a tad more rumble than the SE215 on minimum). It's very fun to listen to, and is also a pretty capable IEM (no slouch at reproducing tiny details in the track), so if you want to get an enjoyable IEM in your price range, I'd suggest the IE80. Ergonomically, they tend not to fit some people well (also because the stock tips are really not very good at all), so do be warned that you'll need to experiment with tips. Good luck!
http://www.amazon.de/Sennheiser-504771-IE-80-In-Ear-Kopfh%C3%B6rer/dp/B005N8W27I/ref=sr_1_1?ie=UTF8&qid=1359584752&sr=8-1
http://www.amazon.com/s/ref=nb_sb_noss/175-3404450-8938458?url=search-alias%3Daps&field-keywords=X10