Best portrait bokeh lens for Nikon D7100?
I just upgraded from a D3200 to a D7100 and am trying to figure out a good portrait lens to purchase for it. I have the 55mm prime portrait lens but I feel like I have to back up too far to get a full body shot of my subjects. Weddings especially make this difficult, but I love the quality this type of lens gives me. My current portrait lens is also FX and I"m wanting the DX to get the maximum amount of quality out of my camera. Any recommendations for an inexpensive lens? (less than $400) I thought about the Nikon 35 mm prime lens. With it being shorter I figured I'd be doing less backing up. I'd rather have to move in closer than back up, especially if my space is limited.
Yes, your best bet is to look into the AF 35mm f/2.8 lens; check out B&H Photo (NYC). For future consideration, you may want to save money and eventually get the AF 17-55mm f/2.8 lens (it is pricey but check the USED camera department at B&H Photo and KEH.com; it will open up opportunities for you for weddings) because it will work better in lower light situations as opposed to the kit counterpart that's AF DX f/3.5-5/6. EDITED: the 35mm lens on a DX sensor is a great walk-about lens (just like the old 50mm lens was used during the goneby film era) but it won't give you the versatility of a zoom lens; you'd have to "zoom" in and out by you physiclly getting closer or further away from your subject.
The Nikon 35mm f/1.8 is relatively inexpensive and, at f/1.8, will give you great bokeh. The 17-55mm f/2.8's bokeh is close, but you can definitely zoom further back when in tight quarters. I have both and they are among my favorite lenses for my D7100.
Here's a recent shot I took (available light, no flash) with the 17-55mm at 17mm and f/2.8. 
The problem is that controlling the out of focus backgrounds relies on a few things
* A lens with a large aperture which both your current "portrait" lens has as well as the Nikkor 35 mm f/1.8
* A lens which is a medium telephoto lens (the 35 mm is NOT that)
* Placing the subject close to the camera/lens (a shorter lens will tend to produce slight distortion of facial features)
* Assuring that the background is at least 30 feet behind your subject
In reality, your current lens is really the right lens to do what you want and backing away from the subject is really your best option.
A note on Bokeh.
Bokeh is NOT just having an out of focus background. Bokeh is the quality of the out of focus background and is totally dependent upon the lens design, NOT your ability to make backgrounds become out of focus.
See the link below
Get the lowest f/numbered 50mm or 80mm (or so) lens you can afford.