Thanks for the info people, I realize the benefits of online printing, but the fact remains I will still have a printer for proof purposes, and as Mr THX says its much more convenient, I do print most at A4 size just for clarity.
If its an album of shots or I really need a high quality finish that will endure then I would get them done online, but even then I would still print off a few myself to make sure the colours were fairly accurate (hence my previous request for info regarding colour calibration - thanks for your info there too
).