Guild Wars 2

I play a WvW necro, so this will have details about wvw necro gear in addition to general information, specifically for a marks-based build (power/vitality/condition dmg)

1. Crafting
Crafting is the best way to get max optimal stats (exotic) armor at level 80 for this build. You can either use the TP to purchase the crafted gear (1-4g per piece) or level crafting to 400 (tailoring for necro). This should cost 10-15g to level plus using all relevant raw materials you got on your way to 80. Getting the materials for crafting the actual armor is also expensive, perhaps 1-2g per piece. I was able to purchase one of the weapons for 3.5g.

2. Dungeons (badges only)
Unfortunately only one dungeon has the right stats exotics, but the set bonuses are off. This means the runes will have to be replaced. A dungeon set requires ~45 dungeon runs, so plan accordingly. Dungeons are not a walk in the park to pug.

3. WvW (badges only)
WvW only has one set of exotics, power/toughness/vitality, which is a pretty weak stat set for WvW for a necro (and other dps builds). It cannot be purchased with karma, and costs about 250 badges per piece. This should take 100-300 hours of WvW, depending on how well your server is organized for WvW.

4. Karma
Only available in the Orr zones, you can purchase exotics from karma vendors that spawn from completing dynamic events. The cost is about 45k karma per piece. I did not see a set with optimal stats, though some mix-and-match might be possible. It seems to be the only way to spend karma for exotics that have somewhat decent (suboptimal) stats.

Does gear make a difference?
The difference between exotic and the previous tier is 13%. With base stats included, the difference is roughly about 4-5% actual damage and health over the previous tier, which certainly is enough to make a difference, especially during siege and versus non-level 80 characters in WvW, and less so in siege defense situations.

In essence, there is no quick power plateau upon reaching level 80. Your character gear selection choice will be limited to a single upgrade path following one of the choices above based on which stats set is optimal for your build. And to be perfectly clear, ensure you are using level 80 exotics, as the amount of stats is of course based on the item level, and some vendors might offer different level exotics as well as level 80 gear.