Macports is my tool of choice, but yes it's the only way to get things done! Unfortunately, plenty of scientific libraries are too obscure to be ported, leaving it to us scientists...

Interesting what you say about 10.8 - I might give it a shot then. I will be upgrading soon from snow leopard (2009 MBP) and I was going to wipe and go debian/XFCE, because of all the "new ideas" like "let's not have save as" etc, but if installing stuff is easier (and I know multitouch works) I might give it a go.

I halfway solution I'm reasonably happy with is to have a VirtualBox install of Debian on top of OSX, and install most scientific libraries there. I've considered just wiping and installing Debian as the main OS, but when I first looked the Linux driver support for my MBP wasn't great, and since then I just haven't gotten around to it. VirtualBox works fine for anything that isn't too heavy duty, and anything heavy-duty I'm running on a beefier server machine anyway.

This is a good idea. The problem I have is that I sometimes need basically all my RAM for simulations (yes, occasionally even on my laptop) and my current only has 4GB (with OS X eating up about 1.5GB on startup for "kernel tasks") so it's dangerous to run a VM with more than 2GB. New laptop will def have 8GB though, so this solution becomes viable again, thanks :)

Oh no, I think slapping linux on it is the way to go, don't get me wrong :)

But I got stuck with it because I had to do ios dev at some point, so I learned to adapt ...

I hear arch and ubuntu both work great out of the box on macbooks.

hmm, If I can get Arch to install, I might give it a go. Ubuntu was a bit pants when I tried it for a month early last year (had installed Lion, was pants on the old machine, tried ubuntu before rolling back to SL.) Multitouch gestures for multiple desktops is a must now that I've got used to it...