Both are really important, honestly. You will get perks quicker than you suspect, especially because those 2 skills are really easy to power-level if you have disposable income. Fortunately, a skilled enchanter and blacksmith will be able to buy materials and sell the finished goods to the same merchants for profit.
Early on, invest most of your perks on the stuff that keeps you alive (via boosting your survivability or your ability to kill quickly). After 10 or so levels of nothing but weapon, armor, and blocking perks, start smithing and enchanting. Make iron gear (daggers are most efficient) and enchant them with whatever you know that has the largest impact on their value. Sell those daggers to get a nice profit. Work you way up the right side of the smithing perk tree (because that's the side specifically for heavy armors).
The reason smithing will be so important (beyond the synergy with leveling enchanting) is that improving weapons/armor after you get their respective perk is a huge benefit. With my smithing in the 80s, I am easily adding 20+ armor to each piece of armor I wear, and 10+ damage to my weapons. Since I happen to dual wield axes, that's 100+ armor and 20+ damage for the low cost of 6 ingots (one per piece improved).
tl;dr: do both. After a little bit, perks are easier to get, both skills are very very good, and the two skills really benefit one another nicely.