It really depends on what motivates you.
For many working out at home is better because they don't have to go anywhere.
For others, they need the external motivation that going to a gym can provide through other members, staff and/or instructors.
I prefer a mix. I have a free membership at the gym because I teach there at times during the year (Turbo Kick, PiYo, Pilates, and Yoga).
At home, I like the Turbo Jam series (but I was predisposed because I was a Turbo Kick instructor before the release and there are snippets of me in the informercials.) I own most of the beachbody products (P90, P90x, Hip Hop Abs, Yoga Booty Ballet), several Firm products/kits, and a ton of other products out there from bellydancing to Tae Bo to Hula to you name it.
I often will use my instructor DVDs (for TK and Hip Hop Hustle (new gym class from TK company) to work out at home. I, honestly, am MUCH more motivated leading a class than working out at home because I have the attention span of a gnat.
There really is something for everyone out there. Collagevideo.com is a great place to check out home videos because they offer 60-second previews of every video they sell.
One of the most important things to see change is to keep your routine fresh. It is important to mix cardio and strength training. It is important to change things so that your body/mind doesn't know what to expect.
Good luck!