With a toddler, I'd recommend any of the Monorail resorts if you can possibly swing it. Magic Kingdom will be your primary park if you're concentrating on your son's enjoyment and the ability to take a quick Monorail trip back to your room for a break will be well worth the money IMO.
Talk with a trustworthy Disney-knowledgeable Travel Agent [They're a sponsor here and I can't recommend them enough - Kingdom Konsultants are excellent!] and they can help with getting the best possible discounts for you and keep your booking updated with any new discounts as they come out. Depending on how long you plan to stay, discounts at a Deluxe resort can be quite good at that time of year [January, after the holidays].
If the Monorail resorts are still too expensive, I personally love Port Orleans French Quarter amongst the Moderates. It's small, quaint and very pleasant.
With your toddler, plan to take lots of breaks and relax. The longer your stay the better, so you can still experience lots without burning the little guy out. There's nothing worse than dealing with a tired, cranky child that's experiencing significant sensory overload [which is very easy to do at WDW!]. Make sure to take lots of pictures/video of the boy with characters, on rides and everywhere. He likely won't remember much in the way of specifics, but he'll remember having fun with Mum and Dad and a good photo/video album will help perpetuate the memories.
Also, if you're there for a while, don't be afraid to book a parents' night out. There are babysitting services you can hire that will come to your resort room. A nice, romantic dinner and a bit of adult time in EPCOT can be a wonderful thing.
For meals, I wouldn't book very many, if any, table service restaurants. Trying to time meals to when the boy is ready and not tired/grumpy is virtually impossible. There are lots of reasonably good to great, sometimes even nutritious quick service options available and during January walk-ups at Table Service restaurants aren't entirely out of the question.