Hot Water Heater Recommendation?

just took a freezing cold shower - not fun. Time to replace the hot water heater, it is 15-20 years old an as the home inspector put it "past its useful service life".

I was looking at the tankless on-demand heaters but since I don't expect to be in the house long enough to realize the savings - and I will be installing myself - I'm just going to go with a standard gas-fired heater. The current heater is 40 gallon and I was thinking I would bump it up to 50. Does anyone care to make a recommendation on a unit they really like. I'm not generally motivated by price alone, so I am willing to pay for a good quality heater.

thanks in advance for any advice.
Sean

The only 2 brands I would consider is Bradford-White or Rheem.

thanks for the recommendations Cass - that should help narrow my search.