I knew doubling my RAM from 4 GB to 8 GB would improve performance but not THIS much! My boot time from complete shutdown has dropped to about 1/4 what it was (and it wasn't bad to begin with)! It's like everything just pops on the screen at once instead of each startup program loading separately...like my menu bar just populated all at once! wow! I ended up going with Lexar RAM because that's the only brand Best Buy / Future Shop had in 4 GB modules. It was also very easy to change it myself! (I was a little worried at first) My only hiccup was I didn't quite have the bottom module completely snapped all the way in so first boot showed 4 GB still. I knew right away that was the issue because it just didn't seem like it was fitting right when I first put it in. I just had to push a little harder. Rebooted again and 8 GB! (as a side note..... how CUTE are those little tiny screws holding the back on!!?? LMAO) btw... I'm a girl, so I am allowed to use that word! This is a mid 2009 13" MBP 2.53 GHz Core 2 Duo.... At this point I don't think it's worth me upgrading to a newer MBP because the processor speed still seems plenty, and I run Adobe CS5 and a bunch of other graphics tools on the go. You might wonder why I didn't get a larger MBP... it wasn't a money issue at all. It was the size. I wanted small and light and portable. So I could bring it in my camera bag to do on the spot editing. At home I plug into an external monitor. Next upgrade will be a larger HD. But I don't know how much of a pain is it to switch to a new HD now? I don't have SL install DVD... my Time Machine backup is Lion. Can I get this HD imaged and just copy the image over to the new HD and have all my apps still working normally?? The 320 GB hd I realize was already an upgrade (since it came with a 250 GB) but I had that done when I first got the MBP so Leopard was already installed on the 320 GB.