What to upgrade to from B652/SUB-80?

So here's the cheapy setup I'm using now:
-DA B652s ($30)
-DA SUB-80 ($80)
-Xonar DG ($25)
-vintage Hitachi HTA-3000 ($10)
A little obscure, here's what it looks like Warning: Spoiler! (Click to show)

I feel like its time to upgrade as I have some money and my computer is set for awhile.

Speakers:
Here's what I've been looking at
-Infinity Primus 153 ($150 Amazon). From the OCN recommended thread, haven't found alot of reviews of it elsewhere
-Boston CS 26 ($150 Crutchfield). Found a good amount of positive stuff on the web for these.
-Polk Monitor 40 ($140 Newegg). Pretty good reviews, cheapest of the bunch.
-NHT SuperZero 2.0 ($200 Amazon). More than I want to spend but very good reviews and on OCN recommended thread.
-??? Any other options I should be looking at

Also is it even worth upgrading to any of these? Or will they be not be noticably better than 652s?

Sub:
Pretty much set on SUB-1200 for $125, BIC F12 is too expensive.

Sound card:
Probably Xonar DX ($90) or maybe HT|Omega Striker ($80). Not sure if its worth the upgrade though, some people can't tell the difference between the DG and the DX.

Amplification:
Very happy with what I have now. Possibly a Sherwood RX-4105 ($100). Not really interested in DTA-100 or similiar as I like listening to the radio while I'm working on my rig.

I'd love to hear what you guys think, what you personally would upgrade next and/or what your thoughts are on the stuff I'm looking at (bookshelfs primarily).

Primarily I listen to rock and electronic music, and these will be used with my PC so they will be for near-field listening. Room is the basement, pretty large with bare floors and concrete walls (lol...).

Thanks in advance

Yeah, definitely good reviews for the BS21s. I didn't really consider them because I was looking in the $100-$200 range but if they are better then the more expensive speakers I'm looking at then no reason why I can't save a few bucks. Will do more research on them.

Thanks for the input, +rep

Looks like its 30W RMS x 2 @ 8ohms. B652s are also rated at 87dB. If my amp doesn't have enough power will it just lose volume or will it affect SQ?

The Boston's are $76 a piece, but I just realized they are open box. Given their price does that make them a more attractive option?

Otherwise it sounds like its not worth upgrading unless I drop more than $200.

Although if the BS21s go down to $50 again I might grab some.

Thanks for the advice, +rep.

Just did some research on the S30s and they look like a very good option and for $220 a pair they aren't much out of my price range. I'm glad you and aksthem1 brought them to my attention

They will be used with my rig on my desk, so they would be roughly 3 feet away.

Will check out ebay as well, thanks for the advice, +rep.