I want the Big Angry Bomb, Gran Faust and the Argent Peacemaker, but, as you might imagine, I don't have bottomless pockets filled with never-ending crowns. I want an educated opinion on what to get first. Here's a few details on what I already have and reasons why I want these weapons:
Gran Faust: I have a level 5 Faust and the (learned) Recipe, and a Divine Veil which I use near-permanently. Good at killing Gremlins, and I like cursing stuff (BTW, what can't be cursed? I'm not entirely sure myself).
Argent Peacemaker: I have a level ten Silversix with Undead low, and the Deadshot Mantle (no recipe). Easy to use, and theoretically very useful against my preferred foes, but according to the wiki it isn't that much more powerful than the SS.
Big Angry Bomb: I have the three star blast bomb at level five, and the three star demo suit and helm (No recipes for the Tier 3 demo gear - I'm not going to get Volcanic just yet - or Big Angry). I don't have a Tier 3 bomb, and the Big Angry has a huge radius and supposedly does more damage per hit than it's siblings. Plus nothing says "[Screw] you, Basil!" than a BAB in his face. And I hate minis.
There's not much else to say. I currently actively use the Divine Veil, Volcanic Plate Mail/Charged Quicksilver mail/Deadshot Mantle*, Cold Iron Vanquisher and the Master Blaster/Setenza/Silversix*, if that helps.
*depending on the scenario.
I don't think there's a good answer. It really depends on how you play, and what enemies you have trouble with the most.
Goblins and Slimes murdering your face? Get GF first.
Machines and (mostly) Undead making you regret being amongst the living? Get Argent first.
If you really hate small enemies, Bombs always goes well.
It's really up to you.