I can not stress the importance of a decent set of speakers. I started off by buying one of those cheap setups with 4 speakers and a sub woofer for like $20. I don't think the difference between that set and the two speakers on monitor could even be measured, much less heard.
I have one of each of these:
<A HREF="http://www.bestbuy.com/site/olspage.jsp?id=1061770059306&skuId=5999324&productCategoryId=cat01055&type=product" target="_new">http://www.bestbuy.com/site/olspage.jsp?id=1061770059306&skuId=5999324&productCategoryId=cat01055&type=product</A>
<A HREF="http://www.newegg.com/app/viewproductdesc.asp?description=36-121-114&DEPA=0" target="_new">http://www.newegg.com/app/viewproductdesc.asp?description=36-121-114&DEPA=0</A>
I purchased the Logitech set locally at BestBuy for just under $50, the Creative Labs set came locally from CompUSA, again just under $50.
Both these speaker sets have an unbealivable amount of bass, you would think you had a 12" subwoofer hooked up (Bass can be adjusted if you don't like your desk vibrating). Both, in my opinion, are crystal clear, they reproduce sound just as good as anything I have heard. Both systems are capable of playing at very loud volumes without distortion.
Now, what I think is different, the Logitech set, I think, is capable of producing a little more bass than the Creative Labs set, most likely due to the larger sub.
The Creative Labs set has a wired remote for volume and bass, which is a huge plus. If you use it, you will like it.
Both these sets are made by well-known companies, and can be picked up at local stores without breaking the bank.
For reference too, my Logitech set is roughly 2 years old, and the Creative set is coming up on about a year old, still no problems.