How many?

Well, let's do some math (for the sake of an accurate answer).

In the base game, there's a total of 8 elements, each of which having 4 characters, which starts things off at 32. 4 of the 32 were only available in Adventure Sets, in which each of the 4 available included an area figure, and 2 magic item figures. Then there's the character variants, such as Dark Spyro (which was 3DS exclusive) and the 4 legendary figures, and the total number of figures reaches 49. Then there's the Volcanic Vault Battle Arena figure (which was a Best Buy exclusive), and the 4 Frito-Lay exclusive Sidekicks, and the final number (without counting the limited special editions such as Blue Bash, Silver Spyro, Red Drill Sargent, or Crystal Clear Wham Shell) is 54

As for Skylanders Giants, we still have 8 elements with 4 characters each, which again starts us off with 32. Adding onto this are the 8 Giant figures, and 8 new Light Core figures. Add the new Dragonfire Cannon Battle Pack figure, and the total reaches 49. Then there's 15 new variants (Legendary Stealth Elf, Legendary Bouncer, Punch Pop Fizz, Legendary Jet-Vac, Granite Crusher, Legendary Slam Bam, Legendary Ignitor, Gnarly Tree Rex, Royal Double Trouble, Scarlet Ninjini, Polar Whirlwind, Jade Flashwing, Legendary LightCore Chill, Molten Hot Dog and the Golden Dragonfire Cannon Battle Pack), and 4 more sidekicks (to be released), which brings the grand total (excluding limited special editions like the glow in the dark Cinder) up to 68.

So, for a final count...

Figures for Skylanders: Spyro's Adventure
32 Standard Character Figures
4 Adventure Set Area Figures
8 Magic Item Figures
5 Variant Figures
1 Battle Arena Figure
4 Sidekick Figures

Total = 54

Figures for Skylanders Giants
32 Standard Character Figures
8 Giant Figures
8 Light Core Figures
1 Battle Pack Figure
15 Variant Figures
4 Sidekick Figures

Total = 68

Grand total for both games = 122

Again, this does not include the special edition figures, such as Flocked Stump Smash or Golden Flameslinger. This is mostly due to there being no difference between those and the regular figures, in terms of appearance, and/or stats in game.