I use the Adam S3As. They do not sound fun or nice but they translate incredibly well, I never ever get surprises when I take mixes or masters out of the studio. A key thing about them is the lack of fatigue factor, very easy for long sessions. I had the opportunity to hear most of the range at the AES a few years back and the family characteristic seems strong, the little guys had a lot of what worked about the S3As. Really really nice people in Adam too! I've had the K&H O300 in the room with them for a few weeks and they were nicer and more musical to listen to but ultimately not as good for making decisions (for my ears).
I've heard some PMC IB1s which I really liked, some older ATC SMC20s which were comically bass shy. Used to mix on Genelec 1031s for years, glad I don't have to any more, very tiring and questionable translation. Worked on a set of big Genelec 1037s with a sub for a few weeks, sounded fine to me but I wasn't mixing. Have mixed on NS10s, no fun but I find they translate well. The only Questeds I've heard were the VS3208 (I think that's the model) in Dave Collin's room in LA, really liked them.
A friend has a set of the big Geithans but I think they're broken, they sounded so bad when I was tracking there that I switched them off and set up the Adams. Used the Meyer HD-1s, wasn't crazy about em.
Monitors are a very very personal thing. Other people's opinions are practically worthless (so why have I given you mine??
). You have to try them in your space with your ears and your style of mixing. Don't buy the nice sounding speakers! Buy the pair that make your mixes sound good in the car, boombox and ipod. If you are not experienced with setting up speakers in a room get a buddy to help. Sitting there flicking the "eq" switches randomly is a recipe for disaster.
Do you have a ref cd of tracks you know well and have listened to on tons of systems? If not make one and use it to audition your potential choices.
Good luck!
Ruairi
BTW it looks like I'll be selling my S3As in the next month or so after 4 happy years. I have an offer of a pair of PMC MB2 which I can't refuse, it will be a step up for my mastering work I hope.