Who could be the "Half-Blood Prince"?

[w1blade]

No: HPFGUIDX 107939

After hearing the title of the 6th book, I got to wondering who 
the "prince" might be. The person that pops to my mind is Seamus 
Finnegan. I don't remember if it was in the book, or just in the 
movie, but when they are eating their first meal at Hoggwarts, 
Seamus pipes up with, "I'm half-n-half. Dad's a muggle, Mum's a 
witch. Bit of a nasty shock for him when he found out." Now I can 
only assume, that unless there is one that will be a first year in 
book six, it has to be Finnegan. Anyone with a different idea? 

"w1blade"