In your case, a minimal setting would probably be best. The aperature size is how much of your regular RAM you dynamically use to help your vid card. Since you have a card with 512MB already, there's not much sense in tying up your RAM.
However, that RAM that you assign to the AGP slot is, as I said, dynamically used. That means that it is only used when it is needed, and remains part of normal RAM when it is not needed by the vid card.
Intel E6750...........PSN: ELBATROP
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Patriot PC2-6400 8GB (4x2GB)
36GB WD Raptor
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Samsung SyncMaster 750s
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