For multimedia speakers the Promedias are ok but there are alternatives. For instance the Diva Swans M200 will sound better, while they may not extend as low as the 2.1's the clarity is above and beyond any promedia system. http://www.av123.com/diva.shtml
there are also things like the Videologic Sirocco Xfires which would be direct competition towards the 4.1's, 5.1 for the multimedia market is still growing but you could throw in the Megaworks 510d's and the new Logitech 680's. But you can still go higher with some bookshelf speakers and a reciever, which will no doubt cost more, but should be worth the money if you invest in good equipment.