Cem, there are so many great papers to use with the 3800, that if you don't have a feel for the paper you like already, I'd recommend ordering some sample packs and try them. The new baryta papers are all very nice (well, haven't tried the Hahnemuhle). I ended up with the Ilford Gold Silk Fiber because I, too, like a warmer paper--and the prints are lovely from the 3800--both mono and color. The Epson Exhibition Fiber is worth trying---beautiful, though very cool--and pricey. One hint for using the back single sheet feed with these heavier papers (though some are printing from the center feed--but one at a time)---use a bit of light pressure as the paper is pulled into the feed--and continue to hold onto it until it 'settles'. This has given a number of people fits.
There are a number of papers in 17 x 25 sheet available also--Inkjetart, Hawks Mt., and Red River. If you print panos, you can do up to 37.5"--I'm not a big pano printer but had to try it. I cut 40" paper from roll semigloss and it printed beautifully. I will also say that I've had mine since Dec. 2006 and have yet to have a clog--and I don't print every day--sometimes it sits for a good while (off) and then I print quite a number at one time.
Diane