I don't even bother with printing pictures at home anymore. My local Costco has a fully-profiled Noritsu printer and will do prints up to 12x18 in stunning quality.
Oh, and the price can't be beat: 12x18 for $2.99 a print.
I have three 12x18s on my wall at work and no one can believe they were printed at Costco. If you print a lot, the membership is totally worth it. If you shop there a lot anyway, the prints are a fantastic value add
Neil