Wow, that's a toughy. I'm going with the Netherlands although both teams are great. As soon as England went out, I threw my support in with both of these teams because neither have ever won the World Cup. The Netherlands have been to the final twice, losing to Germany in 1974 and to Argentine in 1978. Spain have never been to the final but are reigning European champions.
Key for the Netherlands is their defense which have had to cope with several changes throughout. Van Persie has been rather disappointing but Snijder has more than made up for him. Kuyt is an incredible workhorse, probably the hardest working player in the entire tournament.
For Spain it will be key to get more players creating rather than just Villa and Iniesta.
Can't wait! Should be a treat.