Brand new Macbook--Partitioning woes

Question

I purchased my first Macbook this week. Apple Store said to run software update after I got it set up, so I did, a lot of stuff was installed.
Read up on partitioning under Leopard, went about partitioning it into 2 equal size partitions. It went about "Modifying Partition Map"--then just kept going, going, and going. After about an hour and a half I got on my iMac (Tiger) and googled, found the same problem here:
http://forums.macrumors.com/showthread.php?t=467884
--with no real solution. I didn't want to wait 800 years for it to finish, so I forced quit Disk Utilities, and got a dire warning something to the effect, "Quitting while a process is taking place may render your drive inoperable." Yikes!
I waited another half hour and force quit, anyway. Macbook works fine as far as I can tell, though I haven't used it a great deal. Shows same free space as it did before this.
So, any hints before I try again? And any hints if the same thing happens again?
The main reason I want to partition is because I like having all my media files on one partition, everything else on another. Plus, I use the "erase free space" procedure on a regular basis, and it does this quicker with smaller partitions.
And yes, it was GUID, and MaxOSExtended(Journaled).
Thanks!

Answer 1

I purchased the Macbook on Tuesday. As my details show, it was a white Macbook with Superdrive, therefore it had a 160 GB hard drive. I came home, set it up, ran software update. That's it. Shut it down, went to bed. NOTHING else was on it.
The next day I attempt the partitioning. NOTHING else was on it except what came with it and what was installed with the software updates. Which, just guessing without looking (I'm on my iMac, trying to resolve this without messing too much with the BRAND NEW Macbook), takes less that 16 or so GB, leaving about 140 GB of NEVER-BEFORE-USED free space.
So I appreciate the responses, honest, I just don't see how they are applicable. Certainly a brand new Macbook doesn't come "severely fragmented" out-of-the-box.
Could there have been some type of indexing or such going on in the background (the new updates?) when I attempted the partitioning?
I will boot from the install DVD (which I haven't even touched--everything is pre-installed), run disk repair, then attempt the partition from the install DVD. But if this is necessary to partition in Leopard, why doesn't Apple, David Pogue (Mac OS X Leopard: The Missing Manual) and several hundred websites just say so?
V.K., I don't quite understand what you mean when you say, "the system can not simultaneously access two partitions on the same drive so you'll be taken a performance hit." Is something different with Leopard? It sure worked with Tiger, you have your Quicktime, even iMovie files on one partition (or an external firewire drive, for that matter), click them on and play them, edit them, burn them to a CD, DVD, even though ALL of those APPLICATIONS are on your boot partition. Is that not "simultaneous access" ???? I never ever noticed a "performance hit" on my iMac with Tiger.