The best way to gauge collector interest in to see "sold" listings on
ebay (and other auction sites). A quick perusal of the link below suggests that keeping the pane of stamps in the original USPS packaging will enhance its value a bit (perhaps by 10% to 20%).
http://www.ebay.com/sch/i.html?_sac...+Stamp&rt=ncAs I review these sold listings, the pane has sold for a low of around $65 (without USPS packaging) all the way up to $150 (with USPS packaging). The average seems to be $80 to $100 (the higher values are typically in original USPS packaging).
Of course, one could argue that the USPS packaging may not be archival safe for long term storage. Although you can counter that with the argument that the pane would look better in an album without the USPS packaging so that the whole "pristine" pane can be viewed without the USPS packaging border.
If you're looking for optimum return on your investment, the best thing would probably be to keep it in original USPS packaging. However, its a choice only you can make.