A really good comedian as I don't think we've really seen much over the years get really far.
Paul Burling was great, Les Gibson was good but he kind of fell apart in the final (his script failed him), and Callum Oakley last year could have done with some stronger material.
A magician, or especially, something really original. I wouldn't mind seeing singers, as long as there is a reason as to why they entered BGT instead of X Factor. Of course, the likes of Paul Potts, Susan Boyle, Jonathan & Charlotte, and some of the kids wouldn't go for X Factor, particularly due to the pressure it would endure for them and the fact it isn't suited to them. But The Mend only went through BGT due to the fact they were eliminated from X Factor because they had a management deal, but that rule (which they broke) doesn't exist anymore (well, since last series) but they didn't know, and probably BGT was the better platform for the type of band they are despite the fact it didn't really propel them to stardom, with their debut single only reaching #67 in the UK charts.