Starting this coming year (January 2005) we're switching to the method of having a fixed percentage of each paycheck go directly to retirement savings and not worry about how we spend the rest.
Actually we've always done the fixed percentage method, but previously we always tried to sock away huge amounts on top of that. I've always been a big believer in balance, but trying to save as much as possible, as quickly as possible, always meant tough choices when it came to spending money. So I pulled out the spreadsheets, figured out a reasonable savings amount that will get us to our goal, and that will be it. No more guilt about spending as long as we have the money in our checking account.
I think it helps to have a target date for ER. My husband is eligible for his pension in 2017 at age 44, so our savings goals are based around that. I think without a specific date you end up with a goal of "as soon as possible" and that can end up being a grind.
I've said this before, but I also have a strong sense of my own mortality. The idea of saving money and never getting to enjoy life scares me more than not achieving ER.