If the JK is your daily driver, you may want to consider getting a "beater" if you plan to wheel hard. When you wheel hard, sooner or later something is going to break, and unless you can get it repaired quickly you may be without a needed vehicle. That being said, if you run greens and blues and drive smart, you should be ok building up a daily driver. My old Xterra was a daily driver, and I ran greens, blues and a few black sections with it without any major loss of use (the worst was that it was in a shop for a few days when I destroyed the front diff).
If you go the "beater" route, keep in mind that some components may already be pretty beat, and that may increase the likelihood of trail breakage.
k_enn