MacBook runs extremely slow

hi all. I currently own a MacBook (aluminum unibody model mid 2009) and I want to clean it off before I upgrade to OS X Lion. I recently purchased a seagate momentus XT HD and 4 gigs of memory for upgrades. I was wondering if it would be a better option to reinstall all my programs rather than copying the entire drive (I have carbon copy cloner). I also have a windows partition. Could that partition affect the performance and is it worth reinstalling it? I'm not sure how well it will run with the hybrid drive.

Finally, I have a huge aperture library and was wondering if it's better to move the library to an external drive (my plan is to use my current internal drive). Unfortunately I can only work with usb 2.0, however, I plan to get MBP within the next couple of years. I'm just concerned when it comes to editing my photos. Right now I have my itunes on an exteral drive and it works fine.

I'm guessing my machine is running slow due to the lack of HD space. I have about 50 gigs left out of the 500. This is also why I'm debating whether or not I should keep the windows partition. If you guys could give me your opinion that would be great. I'm fairly new to macs.
Also, what is your opinion on running programs like aperture and itunes on external drives? Is it worth saving the space on the internal drive?

Thanks!

For iTunes it's not really the program itself that eats up huge amounts of space it's the library of media. For example on my system iTunes takes up about 150 MB but the library is approaching 70 GB.

iTunes will easily run with the library on an external drive. It is important though to make sure that the external drive is connected when iTunes launches. iTunes for Mac: Moving your iTunes Media folder

Consider this method.

First find the Original Install discs. Mine like to go hiding whenever a re-install is about to start. As you probably have noticed already, Lion is an upgrade on top of the (very latest upgraded) Snow Leopard. Meaning one must have Snow Leopard installed to go to Lion.

I would not install RAM until after I got the new hard drive in, and it had been working for awhile. Helps with any potential trouble shooting later.

I get speed improvement with Fixing File format errors (with either the original Install disc, or using Onyx (free program)), and a defrag (has been rumored that those who do a lot of media editing have slow down fragmentation).

Fragmentation is not supposed to be an issue for anyone who has ten percent of his file space left. (Or not at all for an SSD, but one still needs ten percent of the SSD available). I have read, one can do an effective defrag by putting the a fresh copy of the OS onto a hard drive then dragging over the data files. Or something like that. The only defrag program I see costs $$ and a lot of time to run, and does not create a better defrag than the free re-install of data. While fixing file formats is not supposed to damage anything, one is advised not to run those programs without having a back up image available.

I would think of doing this. Not changing your current hard drive in any way. Putting your current Hard Drive into an external enclosure without changing it. Putting the newly purchased hard drive into the computer. Installing the OS and the programs you like. Update Snow and all the programs. (Computer must cool off before opening it.)

One can boot the OS from the external drive through the cable by making the choice in the System Preferences/Startup Discs. Personally I wonder if I can get the external box to work faster through the Firewire rather than the USB cable. I do not have an external enclosure that has a Firewire connector.

Many of us here have had a positive experience in purchasing items from OWC. (Performance Upgrades; FireWire USB SATA Storage; Memory, more at OWC) If you do not already have an external enclosure.

Then being the untrusting person I am. I would run Snow Leopard on the new hard drive until I was sure it was working. Since I plan to hold off installing Lion until I feel sure that any surprise bugs are out (that is probably not necessary for any normal person). I would try the new RAM and run the computer for a few days until I felt it was working before I let the Lion roar.

By the means I describe, I would not have to trust any back up program. One only realizes that the back up program failed when the restore is finished and things are missing.

Have fun.