You're probably better off getting a flat panel that natively supports VGA than trying to convert a VGA signal to DVI or ADC. Better yet, get one with both VGA and DVI so your investment is protected if you upgrade computers.
I'd recommend hitting up cnet.com and reading reviews on large flat panel displays. Currently the sweet spot in terms of pricing is the 17" to 19" models, but the really big 20"+ models are falling in price and are at least on par with Apple's 20" Cinema.