The best way to find the quality level you want is to start with;
MPEG-4 under the "File Rendering" tab and use the best quality, i.e. "MPEG-4 25000K" (this will take more time to render so you can set it away and do something else until it finishes, then do the same with "MPEG-4 18000K" and see how that compares. Like this you can work your way down the quality scale until you find what you want).
Also try the same with HDV "NSTC 720 30p" and "NSTC 1080 30p" to see if you prefer those settings.
You can also try "MPeg4 I-frame only" under the "Lossless HQ" tab.
As my final note, I generally go with around "MPEG-4 18000K" in the MPEG-4 options.
You will find that the file sizes of the renders will become larger with these higher settings and hence take longer to upload.
Also if you are not recording video in HD then the HD settings will not improve the quality of what you record. A rule here is to see what quality you are recording in and try to match it in the rendering process.