I use a projector...less space needed in my small home studio and a LOT cheaper - $400 (black friday last year, some toshiba model) and the screen is 80" diag (home made - google a bit and there are 100's of formulas and plans and such for home theatre screens). Screen cost under $25 (painted foam insulation in a pine frame)
I'd like a brighter picture, or perhaps if I could block the light from the only widow I have would work better.
My Spyder2 Pro will calibrate the projector so that's not an issue.
Got it last thanksgiving as I said and shot 2 seniors the next week and used it and ProSelect software. Changing NOTHING else, our average went from $275/senior to $800/senior.
When on locaiton, like this week when we're shooting holiday pet portraits, we use a laptop, ProSelect and a 19" wide LCD (again, black friday was good to us last year) as a second monitor for the client to view their images. Took our pet average from $25 to $78 a person.
Projection is the way to go. Clients are always happy to see themselves on a movie screen type of thing and it will help you get them in a more emotional mindset which will yield bigger sales. Also, it will help you sell your larger prints. Maybe put a sofa underneath where you will project to give them a sense of size that a 16x20 and up will look like in their home.