Well, there are 'native' printer resolutions. Epson drivers, e.g. up-res images to 360ppi if you're using standard settings, or to 720ppi if you're using 'finest detail'. Best to up-res yourself, and don't let the driver do it - the results are superior.
Edit - here some rules that work well for me:
- if your image is <360ppi, up-res to 360ppi and use standard settings (but not 'high speed')
- if you image is between 360 and 720ppi, up-res to 720ppi and use 'finest detail' (again not 'high speed')
LR makes this up-ressing very easy (just check the box in the print module)