If you don't need the portability, the rMBP is clearly a great choice (I still really love mine), but depending on which model you're buying I wouldn't say it's much more powerful. More powerful, yes. Enough to notice? Depends on what you're doing. I ran some tests that were extremely demanding - far more than most users would ever try - and the difference was ~20%. In a less demanding use, you'd never see it, I think.
I won't need it every day. Maybe 10 times a year. I will mostly use my new rMBP on the couch and in bed. It will be used for casual Internet surfing, emails, blogging, writing documents, and doing some picture and video editing.