Just thinking this the other night when listening to samples of the dutch hardstyle stuff on the net. I love pretty much a lot of the underground dance mucic styles - techno/electro/gabba/happy hardcore pre 96/drum and bass/old skool hardcore and house and the hard trance scene always seems to be changing from itself - making it quite interesting and varied - at the moment youve got the melodic german stuff, tech influenced italian stuff and the hard kick drum influnce from holland.
This might be a bias opinion as im not too clued up about the other styles as much as my hard trance but there you go.