I have a Epson 740 that you'll get from me when you pry my cold dead fingers off it. What an absolute workhorse.
I leave it on sometimes for a month without printing and have never had a clogged head. I use cheap generic ink ($4 for black, $6 for color), and I think I've had to clean the heads twice in 5 years.
I've turned it off and forgot about it for a month or so, turned it back on, no problems. I've printed on glossy ink jet paper, regular 20 lb., 50 lb., up to a 150 two sided color copies at a time.
Envelopes are a bit confusing though, can't figure out which side is up (me, not the printer!)
Bought a 785EPX because of the remarkable sevice the 740 has given me.