Ditto what Alex said.
My room is about the same size and untreated. The HT2-TLs sound pretty good in my room. Honestly, they deserve better, but that's another issue. For music, that's all the bass I'd want.
Bass-wise, the HT2-TLs dig a little lower than the STs and still stay clean, tight, and fast. For $4K, they'd be hard to beat. I'd also throw in a mention of the HT1-TL towers for $3K.
Another route to take is a pair of the STs along with a single or pair of Rythmic subs, either directly from Rythmic or custom made by Jim. I couldn't do subs in my living room and keep it wife/kid friendly, so I happily went with the HT2-TL.