1) With a half stack is it possible plug headphones into it and not use a cabinet? I'm getting a cabinet, but I'm just curious.

2) I'm getting a 100 watt Peavey Valveking head, what do I have to look at about it to figure out which cabinet to buy?
1. No

2. Something besides the Valveking cab. Something with decent speakers and construction. Need a budget and location to help further. Celestion and Eminence make good speakers for the most part. Cabs to look for would be Mesa, Orange, Splawn, Avatar, Vadar, Mills, etc.