^^^^^^ As above. I guess it depends on what sort of hard dance/house you're looking for.
If oyu want hard stuff, I'd suggest the likes of James Nardi, Frank Farrel, Marc Johnson, Dan Dyson, Dave Owens, Ben Stevens, Ian M, Paul Glazby, Justin Bourne. Some kiwis on there too - WC, Disturbed, Manik, Donuts.
There is quite a bit of techno on there from the likes of Fil Devious, Alex Calver etc.
Some Paul Maddox mixes too for something different.
Another website I can recommned is www.djtoddpelio.com and go to his MP3 page. Some excellent mixes on there of various styles from some big names.