For the holiday meals, staying on-plan isn't too hard. We have a meat (turkey, ham, or tenderloin), and there are always veggies, salad, and raw veg, so I focus on those. For appetizers, there are lots of good recipes posted here. I like the salmon spread, Giada DeL Spinach dip, deviled eggs, and I'm trying the antipasto skewers this year.
Sweets are a problem (at least for me). The sweet sugar plums are close to staying on-plan (phase II). The South Beach chocolate-cherry truffles are good. Cat had a recipe posted for prune- based truffles, which I haven't tried, but look good.
Life's a journey, not a destination.
It's easier to stay on plan than to get back on plan.