Quick tips:
Scorpion Shield, hover/cj, weave, and set bonuses to get to s/l softcap. I used Maneuvers as well on mine, but it's not strictly a necessity.
take the aoe immob to minimize runners.
build for recharge (in Mids, under 'Window', there is a tool called 'set bonus finder'). DP should be under 35s.
don't sweat recovery too much, a fast recharging DP forgives all sins 
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Budget? There are 200 million inf builds that will get you a long way, there's 10 billion inf builds that can soft cap s/l/e/range, perma hasten (with incarnates), get DP 1-2 seconds from perma, 1900% regen when targets maxed ect. Knowing your budget helps people work things around and get you what you're looking for.
Are you looking for recharge? Defense? If you want to farm AE you can build cheap for recharge and just pop purples along with reds, farming for purples is a little less forgiving.
Anyone else going to reply? I really need a new build :/
Sup doods. I realize that I have posted MANY build requests, but deal with it. This time, I am doing it because I actually HAVE this character at 50. I have seen a DP/MM farming build with 1750% regeneration and 500% end recovery. I have heard many great things about farming on a Fire/MM. I saw the build I mentioned earlier on the forums here and I was wondering if I could replicate it onto a Fire/MM. Of course, I am bad at making builds, so I pretty much copied everything that person had in MM onto my MM powers, and tried to get my Fire powers myself. And I failed. Horribly. I know for a fact that there are people on here that can make good builds, WAY better than I can, and if you guys can build me a farming Fire/MM Blaster then I would be extremely grateful. The build I am using now is not as good as I thought, because I had no idea regeneration could go as high as it can. Or endurance recovery. Please, PLEASE help me out here, as I am an impatient altoholic who has trouble making other characters and getting them to 50 (meaning looking at a build I will be excited, but I will not ever get that character past 25).
EDIT: On the budget thing, I don't really know. Just post whatever you guys can make good at the lowest price possible, I just want to be able to roll in some money on this character since it IS my only 50. Just no Ragnarok's or PvP enhancments, as those cost about 1 bil an enhancment.
Thanks in advance!