Is it a good idea to allow DMZ devices access to the Internet, ie:
nat (dmz) 1 access-list dmzout
Obviously they are accessible from the outside using static nat's but should they be allowed to initiate traffic to the Internet?
Really depends on what applications your DMZ servers are running. If they are using static nats's then you won't need the nat (dmz) 1 access-list dmzout statement as static statments are bi-directional.
Good example of where you may need dmz servers to be able to initiate connections to Internet is for DNS ie. your mail server on the DMZ needs to resolve remote IP addresses to hostnames.