The 990s are great if you like your treble. They've got plenty of deep, tight bass, and great soundstaging. They're great with hip-hop and similar genres, good for rock and metal, but not as much for classical unless you like low volumes, or ear piercing violins. The treble peak is just too much for me though. It's quite smooth, but you may find there to be too much.
Also, if you decide on the 990s, make sure to get the 600 ohm premium version. (Beyer has the most confusing lineup ever...) The 990/250s are the only hi-fi headphone I've ever heard that I really disliked. There are plenty that just don't fit with my tastes, but the 990/250s just plain suck. The bass sounds like a large piece of sheet metal flapping in the breeze, the mids are buried under 6 feet of wet clay, and the highs are like nails on a chalkboard. The 990/600s are quite good though. I would have kept them for gaming and techo-ish music, but I can't justify two pairs of higher end headphones at the moment. You'll likely need an amp for them, but it doesn't have to be expensive.
The Denon D2000s are also worth considering. They have the bass needed for explosions and what not in movies and games, along with decent soundstaging. The bass isn't as tight as on the 990/600s, but it's still quite good. I found the highs a little rough for my tastes, but I'm very sensitive to that sort of thing. You'll probably want an amp for the D2000s as well, to tighten up the bass, but it doesn't have to be anything fancy. A decent receiver with a headphone jack will probably do it for either one. If you already have one, it's worth checking out before you commit to a dedicated headphone amp.