Here's a run down on most of the subgenres of electronic music.
UK Garage is fantastic, but it is swamped with cheesy R&B Garage wannabes like Craig David, so it's hard to get to the good stuff. Future Garage is also very good, and is well worth checking out.
Other than the Prodigy, Big Beat isn't all that great, best to look elsewhere.
House can feel rather sparse and plain to me, but you might get a kick out of it, Check out Deadmau5.
IDM music is only really good if you want to chill out, and not to be fully invested in listening. If that seems you're style, then check out Boards of Canada, and Aphex Twin.
Hardcore is hard to get into, but if you have the taste for hard hitting beats, you will love it.
Despite what you say, Dubstep can be good, if you listen to the originators of the scene (Skream, Burial, Kode 9), and not the daily dose of Brostep on UKF. It's a much different beast altogether, believe you me.
Drum and Bass is an easy genre to get into, but be warned, other than Goldie's Timeless, and a few others such as Pendulum's Hold your Colours, there isn't many noteworthy albums in the genre. it's best to buy compilations if D&B is concerned. The Drum and Bass Anthology is a great place to start, as it has a few selected tracks from each time period.
Now we move on to Downtempo and Trip Hop, which are arguably the best of the lot when it comes to electronic. Great tracks, Very varied, and has a superb selection of albums. Granted Downtempo is a lot easier to get into than Trip hop, so you're mileage may vary, but it's well worth it. Trip hop (a sub genre of Downtempo that orginated in Bristol, England) takes all the best bits of Hip-Hop music, the beats, and the scratching, gives it a Downtempo shine, and makes such great music from it, it is well worth checking out, and is personally one of my favourite genre's (hell I own nearly all the major releases from it).
Also, to help you check out these wonderful genres, look up the wikipedia pages, or go on to Rate your music, a Brilliant site for looking up the best albums for each genre.
I hope i've helped.