Bippie,
Something to consider: IF you're wearing a helmet with a visor, as I do, a taller windshield gives you 2 plastic surfaces to have to see through, and the minute scratches which accumulate on them add up in time to decrease the clarity in your visibility. This is especially noticeable in bright sunlight and with oncoming headlights. I installed a windshield on my 250 (bought at the local Honda dealer, but don't remember the brand) which came up about level with my chin. It did a great job for me in reducing the wind, and especially the heavy pelting I take from bugs.

By the way, my 450 came equipped with a streamliner fairing, and it's got more than its share of these minute scratches. It's hard to see clearly through, so I took it off. Does anyone know if there's any way to buff those out or recondition them? It would be a nice fairing for road trips, I think.