Should we buy London Pass or stick with 2 for 1 ?

My daughter (22) and I will be in London for the first 5 days of June for a palace, history, and FUN blitz. I am Big into saving money, but also big into saving Time. I remember well the half hour I stood in line in freezing rain another June waiting to get 2 for 1 tix to Tower of London. Saved money, but wasted precious time (and nearly froze). The shoot-to-the-head-of-the-queue sounds very tempting but is the London Pass worth it when all is said and done? Please help!!