Instant usability is really important to us here at DMS, and we think one of the packs which best exemplifies this is Massive Riffs Vol 1.  This pack was an attempt to really get to the heart of a lot of dance music genres (specifically trance, hardcore and hard dance)

in order to help you out with one of the most difficult aspects of production: a massive riff!  Getting riffs right is really difficult: you need a certain amount of tension and power, and the riff has to loop well.  However, if the riff loops in a manner which is a bit too obvious, you'll end up with a boring, standard track!  Massive Riffs solves this for you by providing a huge selection to draw from - it's one of our favourite download packs, and that's why we believe it deserves classic status.

From the original MIDI pack description:

"These are the kind of riffs you need to slap on a big sawtooth sound with huge amounts of reverb, then sit back and watch the dancefloor go crazy. We've taken in a range of riff styles, from dark and twisted to hypnotic and uplifting, right through to catchy and tuneful. You're bound to find something you like here: either to fill that gap around your main melody or to sit at the centre of the track itself. Remember these files are copyright-free MIDI, so you can manipulate them in any way you want, or simply cane them to death in your next mega-hit!"

Listen to the MIDI pack here.