I have Several sets of Computer speakers.
On my Desktop I have Altec-Lansing ADA880 5.1 Speaker/Sub, Older system but they work.
On my setup table for client computers I use a pair of Logitech X-140
These speakers use no "wall wort" they plug directly into an AC outlet.
For portable use with my laptop I have a pair of USB poweresd Logitec V20's
Not sure what's good on newer speaker systems... but you don't necissarily need to buy new ones.
Speakers are something that many people are constantly upgrading for no real reason...
Check out ebay