I've used two different manufacturers blades, purchased locally, which have worked very well for me. The better one I can't remember the name ( Tman1973 ownes it now.) The one I'm using currently is made by Royse I believe. They are a bit pricey but not in the long run after inexpensive resharpening, time and material saved with better cuts. Probably not worth while if you are planning on using a cheap table top portable style saw though.
some other sample acrylic blades,
http://www.abbeon.com/adf04/rvblades.html
http://www.carbide.com/catalog/CTSB_...=AMA%2DLB10801
General saw blade selection tips,
http://www.generalsaw.com/resource/plasticblade.html
Here's a really good router bit from Onsrud with a flush trim bearing if you are into that,
http://www.onsrud.com/Products.asp?A...8%3A46%3A15+AM