Tactics Practice

I am really interested in drilling on tactics, but I haven't yet found a way that fits me best.

I have not tried any of the commercial software packages, like CTArt, which may be just what I am looking for, but would like to hear some feedback before purchasing.

Things I have tried thus far have been web sites, mostly:

1) www.improveyourchess.com, which seemed like it was going to be a great site, but the GMs running it just don't seem very interested in the customers.

2) chess.emrald.net, which I actually like a lot, but would like something where I can adjust the complexity and time controls.

What packages have you used, and what did you like/not like about them?

I have used:

http://www.braillechess.net/epd.pl?%25253F

and a good book. (Imagination in chess by Gaprindashvili)

http://www.redhotpawn.com/board/showthread.php?threadid=33770&page=1
Quite easily the best.

This also woryhwhile going through:
http://www.chesscafe.com/text/heisman48.pdf