I am running a similar set-up. I have Mirage OMNI 60's as fronts, with mirage OMNIsats as center and surrounds; my subwoofer is a Wharfedale PC10. My room is rectangular, but is difficult tplace speakers in due to entryways and sairways and such. Personally, I think this system sounds great in my room. The mirage OMNI series really presents a great soundstage for music and it sounds like a movie theater to me. I only recently got the OMNIsats and was previously running with no center and bose 161 surround and I notice a HUGE difference in music and movies now that I am using the matched set.
Music sounds clear and powerful and fills the room completely, I listen to many different types (Elvis Costello, Tom Waits, Melvins, Beatles, Bob Dylan, ELO, etc.) and find these speakers handle it all very well.
Movies sound great too, I have what I call the Lord of The Rings test, where I put in the first disc of the Fellowship and go through the opening battle scene; lots f surround effects and a hige range of sounds from high to low. My set-p sounds as good to me as it did in the theater, you can actually feel the bass when Sauron bites it. With the lights down in the room it feels like the theater (except for the small TV, now if I can only get the wife to let me get a big plasma TV...)
So, basically, I think very highly of Mirage speakers, the OMNIsats definately a good purchase in my opinion. Now, the one caveat, I haven't used the OMNIsats as fronts as I have the OMNI 60's, I have heard them in a dealers shop that was set up as a living room and liked them there, but went with the OMNI 60's because I was afraid they wouldn't hold up as fronts alone (I was buying the system separately and was going to have a period when I was running with just fronts and surrounds with no subwoofer). I might suggst looking into getting the OMNI 60s or 50s as fronts, but if you are getting the entire package deal together, that might not be possible and might not be necessary if you get the sub with the package.
Last, I don't know a whole lot about subwoofers, I have a Wharfedale, which I like, but haven't compared it to much else so I can't really comment on that part. Many people here will swear by SVS or HSU subwoofers, tey have some 10" models that go for around $300 - $400, I think. Hopefully someone else will chime in on that area.