I need help with the audio side


I am a novice as far as high end audio and would like to upgrade my current setup. I have upgraded over the years from an older Bose Lifestyle 12 system (I know I just made a bunch of you cringe) to a Lifestyle 28 system. Then I learned that no highs, no lows, must be Bose and upgraded to a Harmon Kardon AVR 340 with Infinity TSS750 7.1 system. I have stayed with the Infinity's but upgraded the receiver to an Onkyo 804. I have it all tied into a Monster 3500 Power Center to try to clean up the power and used Monster XP speaker cable's and 1000 series HDMI and optical cables to connect the cable box, Samsung BDP1200 bluray, and Roku Soundbrige M1000.
My system sounds decent but I know it can sound better. Way better. I have listened to Definitive, Vienna Acoustics, Boston Acoustics, Polk, and Martin Logan and fell in love with the ML's and how clear and precise the sound was (like what I was listening to was live in front of me). I was looking at replacing the front 3 speakers, but would like some advice on brand/models to look in to. I am on a budget, so I know some of the extreme high end like Wilson audio is probably out of the question. I also need some advice about preamps and amps...mainly do I need them? Can I use the Onkyo as a preamp and maybe just get amplifiers?

I watch a lot of movies, but also love music (I listen to mostly everything except country and would say Pink Floyd is my favorite).

Any suggestions?
brooksd
What is your budget? This will help everyone here give more useful suggestions.

I currently have no budget so, I am jealous of everyone that has one. No matter how big or small.
Yes, please identify your budget. In the meantime, if you like the Martin Logan Xstats and can afford them, then go with those and build yourself a true 5.1 surround sound system. You have a decent A-V receiver now, good interconnects and speaker wire. Focus on the loudspeakers. They will make the largest difference in sound as you know. What CD player do you have?
Lots of recordings are crap. If you want midrange, price, bass, and never bright (when setup correctly) in a speaker...

In one word
Vandersteen

Planar and electrostat are " you are there" kind of sound but not boogie/ rock and roll. (Although I love Soundlab A-1's)
Amplification can do wonders. Current drives speakers not watts. 100 watt class "A" is very powerful. Most Mass fi items do not live up to their claims. A lot of Esoteric gear has the same issue. Synergy is the real concern. For example, a dark sounding speaker can sound great with a bright amp. vice versa and up and down the chain.
I may get shot for this but, the recording, the room it is in, and then the gear are the most important. Source gear importance is probably foremost. Cables and power conditioners are to be used as "icing on a "good cake" to make it "great"
Like Tiramisu ( Oh that sucks!) (I love it!)
Coffee lover?

Save your pennies and look for CAT preamps (signature and better) and listen to different amps with the system. Tube and Solid State.
IMHO
Nirvana may be nearby.

Jeff
Thanks for the responses so far. Right now I would like to stay under $2000. I know that is not much when it comes to good speakers.
For the most part I use my Roku to listen to music. I have converted all of my CD's to mp3's (which I know isn't going to give me the best sound). If I need to listen to a CD, I use my bluray player. I'm trying to keep the setup as simple as possible.
And tiramisu is actually my favorite dessert, and do like coffee.