Generation are the best certainly, but for a breathier tone, Manitas likes the Sweetone ones.

There's a set of plastic ones downstairs too, but I can't remember the make. They seem quite decent.

The Clarke's Original Tin Whistle has a lovely feel to it, it tapers a lot more than most, and comes in a fetching gold and black paint job. It's got the clear, sharp tone that cuts through most sessions. It's also got a square shaped mouthpiece that some players, particularly those used to recorders or Generation whistles, find awkward and take some getting accostomed to.

LTS