It is awesome.
Remember mode is just a very simple way to remember stuff, and it can be plugged into org mode.
The biggie that I forgot is calc. Just awesome.
I've never used calc. I use rpn, an incredibly simple rpn calculator someone I know wrote in like 1998. Why would I use emacs calc? (Curious).
Well, I didn't know about rpn. Calc the stack based thing, but it might have more features.
Oh, I wasn't arguing, I was just waiting to hear about calc's amazing powers.
Here are some odd highlights: matrix http://www.gnu.org/software/emacs/manual/html_node/calc/Matr...
Lists http://www.gnu.org/software/emacs/manual/html_node/calc/List...
Algebra: http://www.gnu.org/software/emacs/manual/html_node/calc/Basi...
Algebra rewrites: http://www.gnu.org/software/emacs/manual/html_node/calc/Rewr...
Programming calc: http://www.gnu.org/software/emacs/manual/html_node/calc/Prog...
And (gasp) Data Types: http://www.gnu.org/software/emacs/manual/html_node/calc/Type...
(mind you, i mostly use the HP-calculator level stuff. But the rest is certainly awesome)
I wasn't an org-mode believer until a few weeks ago, and then used it to bookmark and track notes for a large software project I had to audit, and it was amazing.