At the time I think my choices were 350d, 400d, 20d (although they were proving hard to find) or 30d. The fps was the main decider to swung me towards the 20d or 30d.
Although the 30d is only fractionally larger in size than the 20d (just a millimetre or 2) it was enough to make it feel awkward to hold. I have little hands!
The difference in price also played a part.
The size and weight of the 20d took a bit of getting used to, looking back I probably would have got used to 30d, but I am very happy with my choice. Prior to the 20d my main camera was a Canon S1 IS which I loved - now it feels very light and small when I use it.