My guess is that
1600x1200 Normal
will be better than
1280x960 with Fine.
Actually, there is a guideline of about 200 pixels per inch to roughly match commercial photo printing quality, so for 10x8 prints you might want to go for the 4500's full pixel count of 2,272 x 1,704.
For a few bucks, you could compare test prints of three options that should give about the same file size:
2,272 x 1,704 Basic
1600x1200 Normal
1280x960 with Fine
and then go up the quality scale to
2,272 x 1,704 Normal
2,272 x 1,704 Fine
to see what satisfies your standards for a 10x8 print.
This is partly based on my limited experience which suggests that when choosing between two options giving about the same file size, the option with more pixels and lower quality JPEG compression factor looks much better than an alternative with less pixels and "higher quality" compression. Also, a lot of people say that JPEG compression to about 1/10 of original file size or bigger looks completely fine until you start further degrading the image with significant editing, so the 4500's Normal compression mode (1/8 compression) is probably as good as needed if you are going to do mostly straight prints.
Preferring more compression over downsampling (reducing pixel count) also seems intuitively right: both discard some information to reduce the file size, but the JPEG algorithms take account of knowledge about human visual perception so as to selectively discard less important information, whereas downsampling is a far cruder approach. For example, with images that are more difficult to compress due to lots of fine detail, the same JPEG setting will produce bigger files: it is smart enough to retain more information in with images that need more.
