Most games are under 100 MB. I think I've had one come close to 1 GB but I can't really remember. I have an 8 GB and am doing fine (with music, a movie and plenty of apps). It shall hopefully match your expectations.
Autobahn Polizei This is just Crash Time II basically in the US. It is already an alias (with the US achievement set) for Crash Time II. The games across regions are identical. I don't know what the deal is with titles but generally the US title should be adopted as the main title on Crash Time II's page? This would kinda confuse things as there are later titles in the series released in Europe.
Should I file these releases under United Kingdom, since I don't have any other options (apart from Australia, Japan and United States). I mention this because there are a few games that get released in Germany first but not in other regions. For example, this Xbox 360 title. It is not yet announced whether this game will be released outside of that region.