THe JBL L 880 are $1200 for 4. 150 watts continous 400 max
The JBL L 8400P SUbs are $400 a piece. 12 inch 650 watts each.
The JBL LC2 center is $300. Handles 150 watts rms 400 max
$1900 total
There is much better for the same price. Many suggestions have been made that are better than the JBL's. For instance, I think the Rocket's and SongTower's linked in the very first response are better sounding than the JBL's and Boston's
For what's it's worth the SongTower's are the best speaker I've heard under $3000. However, at $1800/pair you cannot get four of them.
The JBLS handle 400 watts the bostons only handle 250
Rated manufacturer power has nothing to do with how they will perform and how much power they will handle in reality. These numbers are usually wrong. In fact, Audioholics just wrote an article about this.
Purchase based on which speakers sound better, not on their manufacturer numbers.
Have either of you actually heard any speakers in the JBL Studio L line?
I have - nothing special, especially when compared to some ID brands for the price. However, for what it's worth the Boston's sounded like they had a veil over the midrange and tweeter. I didn't like either the Boston's or the JBL's.
Now what have we learned from this boys and girls?

We learned that the only opinion that matters is
yours. Only
your ears should decide which speakers to purchase. This is because (as evident here in this thread) we all have different preferences and hear differently, not to mention our rooms and gear differ. The best way to figure out what speakers to purchase is to go out and audition, narrow the list and then bring the final candidates home for an audition in your own room using your gear. In my opinion this is the only way to be certain that made the "right choice."
GTO - the receiver you plan to get has plenty of power to drive the candidates. Stop worrying about that. Besides, you can always an an external amp using the preouts later down the road.
For subwoofers check out SVS, AV123, Epik, HSU and Elemental Designs. All subwoofers by these manufacturers will beat what your chose originally was in my opinion.
Sloooooow down, do some research and purchase based on sound quality and aesthetic appeal.
Good luck!