Firstly, floorstanders needn't be expensive and powerful - in many (not all though) cases, they are little more than a standmounter with a built in stand (or else the standmounter is a floorstander with half the cabinet missing
).
Examples of this type include Mission 701/702e (although the 702e adds biwirability too), Diamond 8.2/8.3 etc etc.
True, the floorstander will sometimes suffer with more cabinet coloration (larger panels flex more if not braced enough), and may have a slightly different alignment which may aid bass slightly (won't be much though if everything else is designed properly).
Often though, the floorstander is cheaper than the standmounter and a pair of stands.
It's true though that some floorstanders are purposely designed to be such (ie don't have a standmount twin/sibling), and often feature multiple driver arrays, capable of serious volume levels - they are often large in stature too.
In a small room they may well be total overkill and simply look ridiculous anyway - they may also need quite a bit of power to really get going, by which time your ears are bleeding
Something like the Diamond 8.2/8.3? - I really wouldn't worry.
Just pick the one which fits in with your decor the best/looks best to you. In absolute terms there may be minor sound differences, but these are so small that many people wouldn't even notice - perhaps a very slightly depper bass on the 8.3s - nothing more really, and certainly nothing worth getting concerned about, at least IMO.
You'd probably want to avoid rear ported speakers too if you are putting them against the wall (this really applies equally to floor and standmounters)
As to what you should buy, well that's a bit more tricky.
You need to decide how much you want to spend, and really what type of speakers you would like.
Some go for sub/sats, like the Kef eggs. While they can be very effective, my opinion is that they are outgunned for less money by more conventional speakers - but then they are very small and compact, and do look pretty neat too - if size is an issue, you could do worse. Correct subwoofer positioning is vital for these setups to work IMO - as the sub is going higher (in freq) than is ideal really then it can become locatable - and this can be bad news for stereo imaging (depending on the position of course). Somewhere at the front (roughly between the main left and right ? ) is where I'd put it. If you can't do this, I'd really think hard about a sub/sat combo, especially if stereo music is on the agenda.
That said, it also depends on the room - it's hard to be definitive as there are so many variables. What works really well in one room may only be average in another and so on, and peoples expectations are always different.
As you only have a TV in the room, I'd suggest diverting some of your budget to a sofa and some curtains - perhaps even a carpet too!
These really add to my enjoyment