People on Neogaf seem to be averaging 10 hours... which is decent. Not great, but decent. Keep in mind that story length isn't everything. Left4Dead is still $59.99, and you could blow through that in less than 5 hours. The important thing is replayability.
I'm sure you'll be able to grab RE5 for $10 less within three months if you catch a special offer somewhere along the way, but I sincerely doubt any real price drop would happen that quickly for a game of this caliber.
I'm sure you'll be able to grab RE5 for $10 less within three months if you catch a special offer somewhere along the way, but I sincerely doubt any real price drop would happen that quickly for a game of this caliber.