I use Adobe Lightroom 2
much better than Aperture < my opinion
Aperture uses its own database, if you have 200GB of photographes it will copy it to a 200GB Aperture database, total 400GB... which I dont like..
while Lightroom has the option to use your originals.. plus it has more features which i do not use! i use photoshop... download Lightroom v2 trail, I'm sure you will like it