enclose closet? vent questions

I'm thinking of sealing my closet a want to know if its a good idea or should I leave it open and if I seal what's the best / cheapest way to vent 5 x 4 x 8 minus a few feet once sealed. Its a 400 htg supply with 4 the monster sized 2700 cfls from Lowes. . Please comment as I've officially read so many different things I just need a direct answer....PS eventually I'm going to add another 400 but for a while what I have is it
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