Best HT Speaker "package" for under $2500??

get a used processor here and a multi channel amp, and spend the rest on good new matching line of speakers. Others may differ but I think used for youe source is a great idea...buying all the same manufactures speakers will give you the best image of sound possible.
If you already have a good 2 channel rig in a dedicated room maybe look into Definitive Technology for theater speakers...good price and performance for movie sound.

Check these out. I have a friend who owns these and they are an amazing bang for the buck:

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http://www.av123.com/products_category_pack.php?section=speakers&brand=3

http://www.audiorevolution.com/equip/rocket_speakers/index.html

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If you're looking new, according to June edition of The Perfect Vision, you should be looking at Energy act6, Paradigm Atom, B&M VM, Epos ESL3, Mirage Omnistat, Totel Dreamcatcher, Infinity Primus 360, Magnepan MGMC1, Focal Chorus, PSB T55.
If you're looking here used, you ould go up a notch ot two, but it may be tough to find someone schleping a fully matched sytem.
I suggest you get a copy of the Mag, and see if you can back into one of their more expensive suggestions used.

For starters, head off to sites like these: Ascendaudio.com, Axiomaudio.com, AV123.com. You can buy pre-configured packages, design your own, and there even some on sale (Today only! just kidding on that part...). All have excellent offerings in this price range, and all have been highly thought of by reviewers and real people. The "best" part has to be up to you, 'cause your best may not be any of ours, etc. You could even go w/ a more top-end 5.1 combo (at Ascend, for one example, where you can get a Hsu sub in the deal) and still have lottsa $$$ left for content.