Question about JPEG compression...

I will be putting up 800x600 and 1600x1200 pics on my web site.

I made tests with Photoshop 7 and Advanced JPEG Compressor.

I find that the Photoshop 7 "Save for Web" gives very similar results than AJC, unless I tweak it to death, and then, I get about 1-2% less size.

For the 800x600, I get sizes ranging from 48k to 97k depending on the quantity of details that there is in the picture.

For 1600x1200, I get approx 143-250Kb

(photoshop 7 save-for-web settings: quality 20, optimize)

I'm wondering if there is not a way to get better compressors without loosing image quality.

What are your prefered file size for images of size:
800 x 600 :
1024 x 768 :
1600 x 1200:
2048 x 1536:


Suggestions / comments anyone ?