Ive got the D200 too with the 18-70 ive been wondering about the 70-200 (Sigma) its quite a bit faster than the 18-200 and by the time you get too 135 you at 5.6 (on the 18-200) where as the 70-200 is 2.8 throughout
displays can be quite expensive to repair/replace and since the 350D is an older model (newer ones dont have lcd on top) parts might be harder to come by and therefore more expensive. If your looking for a quote you could try image supply systems in dublin