There's a cap. I believe it's +32% Fortify Alchemy or Fortify Smithing on each piece of enchanted gear, +29% for the Fortify Enchant potion, and +130% for the Fortify Smithing potion. I could have some of those numbers mixed up.
This is without the restoration loop that you can use to get any percentage bonus. It's an exploit and I'm not familiar with how it works.
SupremeZero posted... There's a limit on the RELEVANT bonus for smithing (500-something is max usable armor). I dunno about the rest.
Weapons don't have a max, so you can smith them to Oblivion if you want. As for armor, better smithing lets you get max armor out of cheaper sets, so if you want you can avoid spending perks too far up one side of the smithing tree.
You cannot enchant "Fortify Enchanting" enchantments, so you'll need alchemy to buff your enchanting.
There is a cap, but your numbers are off. For enchantments on items, the cap is 49% for fortification bonuses such as for weaponry. Without the alchemy loop, and using 25% enchant elixirs found in stores, the cap is 45%.
You can also break the cap via an exploit or the console.
According to this page, http://elderscrolls.wikia.com/wiki/Smithing, the caps are: 37% for the Fortify Enchanting potion, 29% for the Fortify Smithing and Fortify Alchemy enchants, and 147% for the Fortify Smithing potion.
These numbers all assume the Falmer Helmet glitch (you get to wear the Falmer Helmet as well as a circlet, and have enchants on both).