Try this before upgrading
We all have extra amps and speakers hanging around collecting dust - so you might want to try this before upgrade bug gets you once again.
Connect 2 amps (RCA "tape out", to "tape in" on another amp) - now you have 4 channels. Connect 2 sets of speakers, and experiment with placement.
You can put them all in the front - giving wider soundstage. Put 2 in the back for surround effect - with good amps unlike most surround receiver. Or you can put two speakers back to back - one firing into a wall - to get omni directional effect - deeper soundstage.
Doing this improves most speakers - it might just cure your upgrade bug for a while - like it did for me.
Another thing you might want to try before upgrading your speakers is a sub. I was listening to $150 Athena bookshelf (AS-B1), and I wasn't satisfied with the sound, although it got a raving review as the best under $200 speaker in the world.
And then I added a sony sub SA-WM500, and bingo - it was satisfying and mesmerising. I was surprised to find this much quality for so little, and it was mated with cheap electronics. I can't wait to bring them home and try some decent units with it. It's my new gym system - it got me so happy and dancing, so it is my exercise solution.
Only the 5 inch woofer gave this pretty sound - I think they are better than a bigger bookshelfs coz they do mid better. You can add a sub for lower frequencies. This way, the mid is separated from the lows, giving them a chance to be shine - giving it a clarity not found on full range speakers.
I hope these inexpensive solutions bring as much joy to you all as they do for me.