It would only take 17% more disk space to rip/encode at the higher bitrate -- probably about $15 worth of disk space, depending on what size disk(s) he has.

Although this is no big deal for your HD in your computer, I think 17% is a significant amount when you're talking your empeg. Let's assume you get 2,000 songs on 10GB:

10GB = 340 extra songs
20GB = 680 extra songs
30GB = 1,020 extra songs
60GB = 2,040 extra songs

So, my point is that you should weigh the options of quality vs. quantity and find a happy medium. This may not be as important to a person with a 60GB, but it should definitely be considered when you only have 10GB.