kat ~ If you do decide on a tenor guitar and plan to do some melody picking, I would recommend using the C-G-D-A tuning and learn the tenor banjo cords. When playing Irish tunes its a bit easier to capo up to the second fret.

If you plan to use it for playing cords and you already know how to play the uke or guitar then I would recommend the D-G-B-E tuning.

The tenor guitar has a sound somewhat similar to the bouzouki which goes along nicely cording for Irish music.

CAP'T BOB