Macbook Pro a bit laggy
I can think of several of things that might be going on.
Have you checked permissions, look in utilities, for Disk Utility. And see what comes up.
How much RAM do you have installed. For better performance I recommend at least 2GB of RAM. 4GB is even better.
Which hard disk did you choose? If it's a 5k, know that 5K is a slow HDD, if you want performance upgrade to a 7K HDD.
I have noticed that when I loaded my Mac up with a bunch of utility programs. You know the type, "this program will solve a specific problem". I I loaded up on many of these programs and suffered problems with my system.