Thanks for the replies everyone - some great advice here.

I like Mick's idea of being challenged (not confusing at all - thanks!) so might bit the bullet and go for standard for the time being. DADGAD seems a more natural progression but seeing as I have my bouzouki for playing Irish perhaps it might be an idea to come back to that later on.

I know nothing about tuning guitars - what is the advantage of drop D over standard? is it just a D difference?