whatever colour you go for it'll look good.
just make sure you do whatever is needed before you fit the engine back for hte last time otherwwise you have to take it out again and agian. stuff like the gearbox mounts, main oil seal etc.
main thing to make sure of when building a beetle is to get all the mechanicals done right first. infact i'd even suggest you leave your car in primer (no paint) till the mechanicals are sorted out over a few days/weeks so there is less risk of damaging the paint at the end.
keep us updated on teh build and take as many pics as possible.