I agree with that, if you're going to go 3-wide, you really want the monitors worthy of it, I don't think 3 properly angled 19" monitors would even fill your view.
For a serious 3 monitor solution think 3 overlaping projectors, but for a budet, then I would say get 3 big LCD, and response time will really only be a major issue for the centre monitor, the surround monitors less to, and even with FSX it's not alot of jerky twitch gaming unless you're in a bad situation, so I doubt response time would be quite as important as for a head-2-head FPS game.
If you're conserving money in any fashion, then spend wisely and get 2 GF8800GT-512 and then desice on you option of SLi with TH2G or Multi-mon on 2 cards, after trying the performance of multi-mon on 2 cards. It give you alot of flexability and doesn't commit you to anyting extra, and is a smashing value when they're selling @ under $200 each.
The only hassle is the whole nV-intel SLi debacle, but the nV boards are still good enough for this to be a better option IMO than 2 HD3870.
Now two HD3870X2s... ... just kiddin'
Although personally I find that ATi's memory management is a little better at the insane end of the resolution scale you'd find on a T2HG, the only problem is they don't like the TH2G as much as nV and so have a little more limitations for configuration.