When I say "best sounding", I mean best sounding to you. Not exactly sure the budget, but the Ascend CMTs are always a good option. They're smooth and clear and the 340s definitely have a lot of that midrange that it sounds like you're talking about. I am not sure they're a huge upgrade over the ILs but they'll have a similarly clean sound.
Ascend Acoustics- Award-winning audiophile loudspeakers and subwoofers for home theater and music, factory-direct. Rythmik subwoofers now available.
www.ascendacoustics.com
Emotiva actually has a pretty good line of speakers now too. I wasn't sure what to think about them when they released them, but I bought a pair on closeout and they're really quite good. Looks like the bookshelf is unavailable right now. Two center options and towers and atmos options.
The Loudspeaker: AKA Speaker - the Voice of Your Stereo or Home Theater System. The loudspeaker converts the electrical signal from your amplifier into sound you can hear, ideally without adding any distortion or coloration along the way, and is the single most important factor in determining...
emotiva.com
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I have always been a fan of Paradigm too.