Hi Ronald, I have been facing the same problem recently. I have D300 and I´m not that limited by money - I could have afforded 85/1.4 but finally I picked 85mm/1.8... Reasons?
1) In practice, the pic quality (on paper, usually A4, rarely A3) between the two is undistinguishable
2) I usually use 2.0 - 2.8 aperture (don´t like when a person has one eye in focus and the other eye hasn´t) and here, I insist both the lanses are equally superb
3) 85mm is smaller and lighter and for me, this really counts.
4) While the 1.4 version is tad sharper on 1.4 - 2.0 (but to notice this, you only have to pixel peep on monitor at 100% magnification; you absolutely cannot see it on A4/A3 paper, I can guarantee that), the 1.8 version has considerably sharper the whole focus plane up to edges; the 1.4 version goes soft much more towards the edges... Please see the MTF curves of these two on the renowned German lens test site
http://www.photozone.de
5) But here is the main reason I picked 85mm 1.8: Both the lenses are rather old. The 85mm 1.4 is even older, I guess about 14 years or so... They are the "D type" and were optimized for 35mm film overall (no aspherical elements, no ED glass, no nano coating etc.). Given the fact that Nikon has already replace their old (but still younger) D versions of 50 and 35mm with AF-S versions, I expect the replacement of 85mm soon as well. Actually I expect the replacement within a year or so at the latest. From this point of view, I don´t feel like spending 1300 EUR on the very old (even it is still good) design.... So I bought 85mm 1.8 in the end.
Of course there were just my steps of thinking, you can see it from a different perspective... which is fine with me ;-).