I've never understood the purpose of asking this question. What difference does it make what others use a computer for? That has no effect on what you may use one for. They can be used for a myriad of purposes, which will differ with every user.
Honestly, I wish I used my MBP to it's capacity, but I never do. I use it 70% of the time for work and the rest as personal, but usually just use my iPad in that case.
At most what I'll do is have 5-6 logmein screens working on my laptop, some excel/word, music playing, and heavy web browsing. By heavy I mean like 10-15 tabs open from forums, or reddit..
But MBP is famed for it's multimedia abilities, of which I use none.