He does qualify for the thread, but while we're talking about him, I'll chip in with my opinion.
He averages 42 in tests, BUT take away that 340, his average falls to 39. Take out his (albeit 3) innings against Bangladesh, he averages 38. Still very respectable - England wouldn't mind having another player or two who can average 38+ - but not great.
Still he is ranked 36 in tests, which seems harsh (alongside Neil McKenzie??!!) and 2 in ODIs, which may not be an accurate overall picture, but does testify that ODI cricket is his stronger form, and his average of 32 with such a high SR suggests exactly that.
Not one of the all time greats, but as Rik pointed out he can also bowl, which makes him very valuable to Sri Lanka, and doubtless one of their best players to date.