I recommend doing the ATPL first if you're doing it here in Europe (EASA). It's what I'm doing. I miss the crap out of flying, but that way I concentrate on my ATPL exams. Remember that here it's 14 exams, not 2, like in the US. Also, that way when I get back to flying, it'll 100% of the time flying and no huge delays between flight sessions. This will keep me fresh and up to date. I recommend you do the same.
@Funnydreadlocks That's exactly what I am doing. I finished my ATPL's almost not flying for a year until now. I just need around 5 - 6 hours to get back up to speed before I head off to Phoenix to do my hour building. That way I can fly full time wherever I decide to do my CPL/ME/IR.
@ Lakhan I will most probably do my IR first too. Reason being, I think it will give me more flexibility on the weather when flying the aircraft.