If you are planning your first trip to Rome you are sure to have the Colosseum on you list of "must sees", and you might know to expect queues at the ticket office. You probably also expect to take a walk through the forum, and take in the views from the Palatine Hill. Why not change the order in which you do things and save yourself up to an hour waiting in line?
The ticket you will buy at the Colosseum is also valid for entry to the Palatine archaeological area, hence the joint ticket can be purchased at the entrance to the Palatine as well. Every time I've visited I've seen queues at the entrance to the Colosseum, whilst five minutes walk away you can simply stroll up to the Palatine ticket office. My advice is to buy your ticket there, enjoy the Palatine, and then go back down to the Colosseum where you can walk past the queue and go straight in.
Personally, I'd rather spend the time on the Palatine in any case but that's another matter...