I commented on each one before, but figured it was kind of useless, instead, here is a summary.
1. Code Less, Deploy Everywhere
2. Make Your Users Smile (without the Today part)
3. Boost Your Development Productivity (without the "(open source GUI)" thing)
Addition... it needs work, so feel free to change it if you like the thought:
GNUstep - Freedom, with Less Code
GNUstep - Less Free Code, Everywhere
GNUstep - More Freedom, Less Code
Please consider all them to be a single thought. Like was already said, some of these phrases don't really say what GNUstep is. I also think we should throw "free software" somewhere in there.