I recently changed from 30" Dell with 2560x1600 (16:10) to Dell 34" with 3440x1440 (21:9). I absolutely love that 21:9 format. That way you might be able to avoid a dual setup, but the 34" screens are pretty expensive, though the 30" was more expansive at that time. Some people don't like 21:9, therefore it's for sure…
And how do you feel about the 21:9 ratio? At work I have 3 monitors and the thing I like is that I can have them at a certain angle, which with a single 21:9 display is impossible.