Well there's lots of defaults, depending on what you want to output to.

If you're intending to burn to DVD, and in PAL land. Select MainConcept MPEG2 in file type, then in the template drop down list below, choose DVD Architect PAL video stream (If the original is 4:3). Then click on 'custom'. On the project tab, change rendering quality to Best. On the Video tab tick 'two pass'. And on the Audio tab tick 'include audio stream'. (If you want audio attached.) You should get good results from that.

If you're in NTSC country, just choose the NTSC equivalent.