definitely. When my old laptop was around 5 years old I took it apart, installed a hybrid HD and took both fans a apart to clean and lube them (one was really noisy). RAM was already maxed out. It made the laptop feel new again. The new HD was faster, both because of the flash and because it was 7200 RPM, and the laptop was completely silent.
It's also a lot easier to take laptops apart than people might think. I'm not a hardware person, I've never "built" a computer or anything, but now I've taken apart both the old and new MBP models and found the process quite easy and fun. The old one was a little complicated, a lot of screws to take out and the keyboard had to be disconnected and removed. Some wires underneath that have to be disconnected to get the HD out etc... The new ones are really easy though, just pop off the back plate and you have access to everything.