I just bought my MBP on Sunday, love the machine. I work in a computer repair centre, not even the most expensive Sony vaio looks and feels as good as this machine does.
In terms of bang for buck it is a very very fast machine, i5 CPU and 4GB of RAM - it doesn't hang about.
I'm totally with what izero said, the mbp wasn't designed for you to go on facebook and a bit of word documents. It can do this with ease but its really meant for the heavy work. I could probably do with jus the macbook, but personally i love the looks of the mbp and the speed.
I bught mine for casual use, and I'd still say it's worth the money.