Some considerations regarding the 3.0's. First, they really want some power behind them, even if you only listen at modest levels. I have a family and rarely can let the system rip the way I want to, but still found the upgrade from 100 w/c Krell amplification to 250 w/c Krell amplification to be an excellent improvement. Second, the speakers are rear-ported which means that they want to be brought out a way from the back walls. It's often recommended that they are out at least 3 feet, which is undoubtedly optimal. My room is 14x18 and I have them out at most about 2 feet - I'm satisfied, but if you're a lot more particular than me, you may not be. A front ported or non-ported design would quite possibly be able to be placed closer to the back wall. The 3.0's are first order x-overs, which tends to yield a more forward sound which, again, is my preference but not necessarily everybody's. A higher order x-over tends to give a wider "sweet spot" and a somewhat "softer" sound which many people prefer.
I don't know these same pieces of information on the 2.5's, but if you can find somebody who can give you the same information that I have provided for the 3.0's for the 2.5's, you'll be set.
Finally, I can't say enough great things about the 3.0's and would never deter somebody from pursuing them. However, you might want to look at the 1.8's (another floor stander) or even look into the 1.3mkII's, a monitor speaker. Their monitors are pretty remarkable - very musical with a pretty extended bottom end - and might fit the area even better along with saving you some money. Just an idea - my guess is that if you buy either of the models you're looking at you'll get years and years of enjoyment out of them.