Can't I get both?
Not for $80-$100 bucks
Actually, even in the $1000 range it's usually still a decision that has to be made. Different people just usually prefer one or the other.
I would indeed check out the
Sennheiser HD280 for $90 bucks new, unless you're looking for something that can be driven well by an MP3 player. You
can drive the 280's on an iPod, but the 64 ohm resistance is pushing it and you'll drain the battery pretty fast. They have rather a rather weak bass response, but have a nice soundscape, are comfortable, laid-back, and immersive.
Another
great value would be the
Audio Technica a700, which you should now be able to pick up new for around $100 or slightly over. I feel like this may be just what you're looking for. The bass is tight and fast, not bloated, and they're pretty decent all around. These aren't exactly laid back, but at the same time they're not fatiguing (too sharp) at all imo. The a500 is great too but isn't that much cheaper so you might as well go for the 700.
And finally, of course, the
Grado sr60/80 must be mentioned. They are far from laid back, but for what they cost they are the best can's out there. They have a very direct sound, and some find them a bit harsh,
but your HK amp should balance them out nicely I think.
Cerwin Vega makes decent low-end speakers, but it's well known that you get much more for your money in headphones, so prepare to be blown away. Please consider upgrading your sound card though, a cheap sound card can absolutely be a deal breaker.