MacBook Pro :: Sluggish System - How To Know About It

a week ago i replaced my stock HDD with a 640 GB WD Scorpio Blue, did a clean install and installed everything all over. Still feels a bit slow though. I'm not sure if i'm just being too demanding since it's a brand new, expensive computer. So i wanted to ask you how your computers perform in simple day-to-day tasks.

I've used Garage band as an example, since i guess most of you have that installed, and could try these things out on your machines, to help me determine if i have a problem:

1. I often, if not always, get the spinning beachball, when i launch not-light apps - fx. MS Excel or Garageband.
Do you guys get that too (the beachball)?

2. Garageband takes 15+ sec. to launch (from click on icon till "New Project" pops up.
How long do your computer take to launch it?

3. When quitting applications, this can sometimes also take a few seconds (not saving anything) and it feels slow.
Do your computer act that way too?

4. Sometimes, when i'm writing a text, fx. in the Safari Google search box, the text "lags" - it doesn't appear right away, but 1-3 sec after i started writing it.
Do your computer do that too sometimes?

5. Right before i posted this message, i was opening System Preferences (i only have 3 prefPanes besides from the standard ones). Even opening that very light app took a few seconds and gave me a beachball.
Do you ever get beachballs from opening and working with such light applications?