Of the systems I've heard, I like Paradigm and Boston Acoustics for their detailed highs and defined mids (the Boston 8 and 10 inch subwoofers are kind of boomy and sloppy though). Paradigm excels especially well in home theater as does some of PSB's larger stuff. Definitive Technology (towers) sound a lot smoother and warmer on the other hand. Klipsch sounds great for movies, but too harsh for me on music. Energys probably have the best frequency range and very linear response (more midrange presence than compareable models); However, the Take 5.2 system could improve power handling a little. B&W is great for vocal and instrumental music but is very particular about speaker placement and room acoustics. Tannoy, Monitor, Mirage, NHT, and KEF make very musical bookshelf speakers. NHT and KEF make great value-added speakers too. The Velodyne speakers aren't all that impressive from my short listening session with them, though their subwoofers still maintain high integrity (CT-120, HGS-10). Polks are IMO overpriced and they are moving in the wrong direction as a company. They're newest speakers aren't much to talk about at all.
These are just a few of my observations. Always listen to various speakers in different sizes and price ranges from different manufacturers before you buy anything! Don't make a purchase off of ONE neighbor/brother-inlaw/buddy's tip. Remember owners are fanatics and can't give you any balanced, unbias advise! Don't limit your shopping experience to only one audio/video store. Visit a fair mixture chain stores (Good Guys, Magnolia HIFI, Tweeter, Ultimate Electronics), and small hifi shops (SF Stereo, Triad Audio) and test the waters. Bring your own demo music or movies when you are auditioning and insist on using them. Choose a disc and song that you are personally very familier with. Remember that well-recorded, high-quality music is always a better gauge of a speaker's abilities than action movies and their synthesized sound effects. When listening to speakers, take note of subtle nuances, the sound imaging, ambience, spatial cues, etc. Don't merely audition speakers by blasting them to outrageous volumes, all speakers sound good very loud. The outstanding speakers can maintain detail and definition at very low volumes too. Don't just listen for clean output, low distortion, boomy bass, and sharp highs. Any speaker can do that, only good speakers can reproduce music with acoustic realism. If you are shopping for an entire home theater system from scratch, remember that the speakers are singly the most important component of the whole system. At least 60% of your audio budget should be allocated to speakers. Good luck in your search for the perfect speakers!