Based on past experiences:
Domestic coach: A319 - I love those monitors that fold down from the ceiling.

International coach: B777 - I love the personal TV's in coach. Big aircraft feel, but you don't feel like you're cramped because the TV's divert the attention. Quiet engines (I sat in the back of the plane), and lovely landing too! I didn't even notice that the plane touched the ground during landing. 3-3-3 coach configuration is also a plus.

International business/first: B747-400 I like the big/heavy aircraft feel for long-haul flights. First class has a high ceiling in the nose section. Business class upper deck gives an exclusive small cabin feel. Lots of room to walk around. 2-2 seating configuration a plus.

- Pat