Today the planets aligned for a pretty amazing set of Unibody MacBook Pro updates. If you want to literally max out your MacBook Pro, both RAM and hard drive have sunk to great prices in the 9to5mac Toys section. Oh, this works in Mac Minis too but removing the HDD might not be your best move.
On the hard drive, Dell has the $99 1TB Toshiba Canvio which has a 12.5mm high internal hard drive that can be pulled (According to this thread) and placed into most newer Unibody MacBooks and MacBook Pros (check your specs). It isn’t a speed demon @5400RPM, but it will likely double or triple the amount of disk space you have. Bonus: You get a USB enclosure for your current Hard Drive and for transferring your data. Updated: A Commenter found 4GB DIMMs at a lower price – 2x$99. I can’t speak for the RAM manufacturer, but OWC ($28 more total) has been extremely reliable in our dealings with them in the past. Here’s Apple’s RAM installation instructions.
These upgrades are pretty trivial and even a novice can do them. There are lots of tutorials out on the net. But as always, no guarantees – if you don’t trust yourself, take it to someone who you do trust! Here are a bunch of YouTube videos on upgrading.