This is of course an extremely subjective choice, and ultimately you'll have to listen for yourself, but I think I can give you a decent look, having only a few months ago completed a revamp of my audio gear which included a thorough listening to headphones. Bear in mind, I'm only an amateur audiophile, compared to the likes of aerius.
First off, I personally hate Bose. I find them too bassy, and I don't like what they do to the sound. The Triport and similar models are also rather uncomfortable, for me. I find Sony a bit... tinny, as well, except for their very high-end stuff. Also, I'm not recommending anything hyper-expensive, like the $800 Grado RS-1's, AKG 701, and such. That's just too much (for now. Don't worry, audiophilia slowly takes over all logic
) Also a disclaimer: other than the 701, I know nothing of AKG headphones, so you'll find them missing here.
If you can have open cans in the office (which will leak sound, how much depending on the particular headphone), one of my first recommendations are the Sennheiser HD555's, with lovely velvet pads. I own these myself, and though they're not the very best, they're only mid-range in price, and sound difference between them and the top of the line isn't huge.
What is the top of the line? In this company, the Sennheiser HD600 is, but you need some power to drive them, and they're costly. Just below that are the HD590's, which have a nice detachable cord, which can be a real lifesaver. Either way, I find all Senns comfortable over time.
They don't even begin to approach the comfort of the Sony MDR-F1 though, those are just wankery. But they leak a ton of sound, being totally open, and I'm fully willing to bet it's too much for an office. So we come to Grado, as Soontir suggested. These have clarity like you'd expect from studio monitors, just without the dryness. The SR60's are nice, but I'd go up to the SR225's, which cost about twice that, but are just brilliant.
The difference between the SR225 and the SR325 (top of the line) is that the 325's have more presence because of that aluminium canister on the sides, but the price is so much higher, that I personally can't justify it. You also have the SR80, which I find too bassy, and the SR125, which is annoyingly EXACTLY in the middle of the SR60 and SR225 in terms of detail. I always found with it that I was being nagged on about how I could have better, if I spent a little more...
Anyways, you may have to get closed cans for your office. Now, here we come back to Senns. The PX200's are nice and folding, and feel sort of like old Koss 'phones, but they sound
bad in comparison to the open PX100's, so I never took to them. The HD212 Pro and HD280's are much nicer, and the latter were actually my first choice for a purchase, before I found the open HD555's.
Sony: MDR 7506 are good, as is, surprisingly the MDR-85 - for the price. I prefer the Senns, though. Not much to say about these, unfortunately, I didn't wear them for more than a quick listen...
Now, comfort... closed cans are generally a bit squishier on your ears, but the most comfortable I've ever worn were the Koss UR20's. Folding, closed, and they cost something like $30. They sound surprisingly good for that, and are free of cord microphonics. If you want something good for little money, they're an okay choice. I'd even recommend them if you want to throw your headphones in a bag and carry them back and forth all day, as if you break these, it doesn't really matter. But let's face it: they're not great.
I'll end on the Beyerdynamic DT 880's, the second most-comfortable closed cans I've ever worn. Are they closed, though? I don't know, apparently. But if you look at them and listen to them, they're open. It's sort of like they went halfway, and the result is pretty nice. They also have the lovely velvet pads, like my HD555's, but mostly, the sound is very clear, and comfort is amazing. More pricey, and they might leak too much, though. So that's my rough guide. I probably missed quite a few things along the way.
Phew, I didn't realize I wrote as much as I did.