Speaker system for MacBook

Is it worth spending money on
Newegg.com - Logitech G51 155 watts RMS 5.1 Surround Sound Speakers - Speakers

as a speaker system for my MacBook...

I was reading reviews of the speaker system and someone mentioned that the speakers sound good with a decent sound card. What kind of sound card is on a MacBook...??

Currently I have very basic speakers and I use my MacBook to watch DVD movies and such (connecting to a monitor)

I have a Creative Labs Soundblaster external USB sound card which I bought for $49 and it works great with my $150 speakers.

But, I believe this sound card only supports 2 channels when used on a Mac. I'm not sure what your options are if you require surround sound.