I will get the Logitech Z640 5.1 Speakers and need to know if my on board sound is good enough

[BigJelly]

I have a Gigabyte motherboard (GA-8IK1100) and it has onboard sound (Realtek AC97) with 5.1 surround sound.
I plan on getting these speakers - Logitech Z640 5.1 Speakers.
I plan on using these speakers mainly for watching DVDs at college (at home I have a great surround sound system). I'm pretty much tone death (can't tell the difference between 96 and 128 kbps mp3 file).
So is my onboard sound good enough for me or should i get a better sound card? If i need a new sound card, what one would you suggest, im looking at these three:
1. Creative Labs Sound Blaster Live! Dolby Digital 5.1 Sound Card ($33)
2. Creative Labs Sound Blaster Audigy ES PCI Sound Card ($36)
3. Creative Labs Sound Blaster Audigy 2 ($72).

Link to Creative Labs Website
Link to Gigabyte's Website for my motherboard

 

[Mem]

I'm pretty much tone death (can't tell the difference between 96 and 128 kbps mp3 file).
So is my onboard sound good enough for me or should i get a better sound card?

It`s really down to your ears and what you`re happy with.I would in your case try the onboard sound with those Logitech speakers and see(well listen in this case) if the sound quality is good enough,if not then I would probably go with the Audigy 2 (option 3 on your list).

 

[BaboonGuy]

get an audigy. the onboard sound will NOT do justice to your 5.1 setup, trust me.

audigy 2 that is

 

[Nebor]

My mobo's onboard sound has an optical out... Doesn't that pass unprocessed digital sound out to an external reciever? Don't some of the 5.1 systems come w/ such a reciever?

 

[stringcheeseincident]

sorry for the semi-off topic, but i have the z640s, and they rule. good choice

 

[JammingJay]

Another vote for Audigy 2.