I've got badges saved up but I'm unsure what upgrade to buy. I'm currently looking at the frost badge helm or the pillars of might and the boots of kingly upheaval. If i purchase the helm, i will loose a lot of expertise that will drop me below the 26 expertise cap and wont be able to be made up except for wearing the experise trinket from TOC, which makes me loose stam. If i dont get the helm, i can be at the expertise cap but will not have the 2 tier set bonus. What do you think is better, the 2 peice bonus or the expertise cap?
It's hard to evaluate which one is better for pure threat, but expertise is certainly the preferable choice for "smoothing out" your tps.
However, it's not hard to tell which is the better upgrade survival-wise and overall - it's clearly the Pillars of Might. They're probably the best piece of gear you can buy for badges - get 'em. 2pT10 is nice to have, but you can live perfectly without it.
No. Spend the badges on the helm, and spend gold on the saronites to craft the legs and boots. Unless you really have difficulty with money, then get the pants made with badges and try to save for the boots. You don't need expertise, your threat is far more dependent on your rotation and spec than your gear.
Also your cloak, shoulder, chest and weapon enchants need to be changed. 30 stam to shoulder, 225 armor to cloak, 275 hp to chest and mongoose or blood draining to weapon.
The 2-pc bonus will more than make up for the threat loss due to lower expertise. In addition, you can use the helm socket to activate your meta, grab the 12 stam socket bonus and stuff full stam gems on the Pillars when you get those too.
So i advise what Dreador said, get the helm and spend money to get the legs made - ie, get both. If you dont have the money, farm it. I'd advocate strongly against getting the saronite with badges, the 184 saronite required could be used to get yourself some kickass fury offspec gear instead. The legs are Best in slot except for heroic 25 gear so it'll last you the longest - well worth the cash investment.
As for the boots, unless you're obsessing over gearscore and have excess cash, i'd first try going after the heroic version of the boots you already have. The crafted ilvl264 boots have only slightly over 1% more EH than the heroic version of your current boots, therefore so not worth the cost.
Oh and the leatherworking +18 stam to your hands - you really shouldnt be needing a threat enchant - if somebody's getting consistantly close, just vigilance them