Upgrading a general use system - Mobo & CPU questions

Why replace the CPU? a little future proofing and an excuse to mess around with some OCing really, I'll fully admit that I don't have a legitimate need for a more powerful CPU(which is why I'm just throwing an AM3+ board at this, just to throw my current chip in for now). It'll be a while before I even consider replacing it though, I'll likely replace the 5770 with an RX460 first.

The stock board is an ATX, but, that's a good point, I forgot about the possible compatibility issues between the Dell case and a new board.
The EVGA White was just a quick pickup from BestBuy after the stock unit died - temporary fix pretty much. I'll probably upgrade the supply in my other rig and use the old(nicer) one in this.

A new CPU just isn't in the budget right now, and I'm just looking to get this setup back up and running. I'm not tied to AMD or any other brand(though you'd be hard pressed to talk me out of the ATI RX cards right now), I just happen to have that perfectly good Phenom II X6, and the AM3+ socket gives me room to play around with some stuff in the future. Hell, I may end up not even replacing the 1045, I'm just focused on getting this system running again so I can get back to working on my new business, the future upgrade potential is really a non-issue.

Haven't checked ebay, really looking for something available at Microcenter(I'm near Columbus Oh) so that I can get running again ASAP(board died yesterday, trying to replace it before it sets me back on my customer work).
You're definitely right about AM3+ being a dead end, but I'm not worried about that since this 1045 is still more than enough processor for what this system is tasked with. Besides, I tend to run my stuff into the ground(computers, cars, tools...), lol, and without my current hardware limiting me, why not? I have me gaming rig(and race car) to suck up all of my money, I don't need this to do it too, LOL.

I just got home about an hour ago and have been checking out hardware(including the G3258+appropriate board combo, but it's just going to push me outside my budget with a new case), and I'm definitely considering the previously posted options - debating between ATX & mATX depending on which cases are cheaper at MC.

Looks like it'll either be this case, one of the better looking cheaper cases that actually fits this gigantic GPU(for some idiotic reason, it has a gigantic bracket that can't be removed[though I work with metal cutting tools daily...] that stretches its length to 335mm) - but with board no more than about $55-60(there are a few open box boards at the C-bus store that are discounted $10-$15)
http://www.microcenter.com/product/467851/Versa_N21_ATX_Mid-Tower_Windowed_Gaming_Computer_Case
or
this ugly thing(open box, stock PSU missing - $25 off) - but with about $70 to get a board with
http://www.microcenter.com/product/467976/Thermal_Master_(Open-Box)_Mid_Tower_Computer_Case

Anyone have any thoughts on these three boards?
http://www.microcenter.com/product/459749/970A-G-31_AM3_ATX_AMD_Motherboard
http://www.microcenter.com/product/444444/GA-990FXA-UD5_Socket_AM3_990FX_ATX_AMD_Motherboard
http://www.microcenter.com/product/426407/GA-970A-UD3P_Socket_AM3_ATX_AMD_Motherboard

mATX boards are out because of this goofy GPU and the aforementioned MSI 970 GAMING is still an option, but the above would save me some cash with some 'open box' options at the local store.

Thanks for the replies thus far, I appreciate the assistance.

I started typing out this update probably 3 or 4 times now, but it's just been so hectic lately that I can never seem to make it to the 'submit' button, ha. But, here it is, the final results. I ended up going with the above posted Thermaltake case and the open box ASRock board and I'm more than pleased with the now refreshed 'daily driver'!










[click the images for full resolution from the awful cam on my ancient GS5]

Don't mind the terrible desk - it's getting replaced this weekend, I gotta have more work space
In the open case shot you can see how LOOOONG that damn 5770 is - just goofy - but it packages will enough with this combo.
I also bought two more 120mm fans(the el cheap'o one just because it was on sale for $3, and, even if it dies tomorrow, I can't complain at that price, and the Thermaltake with a white LED ring because I just can't stand the gaudy colors common in today's setups) to acompany that 120mm that came with the case - the stock one remaining in the factory exhaust position, the two new ones ones, one above the other, on the front for intake. I also had the stock 80mm exhaust fan from the Dell case and screwed it to the second hard drive tray, above the solid state, blowing onto the HDD, and for no real reason other than I had it and it bolted right on there.
The reader/burner drive fits in the case perfectly, but isn't currently usable unless I buy some low profile RAM(can't connect the cables). Honestly, I'll probably just remove it - I can't remember the last time that I actually used it...

All in all, everything packaged very nicely, and I was honestly surprised about the build quality of this case for the price. I'm going to hit the plastics with an automotive satin clear coat in the future because I can't stand how impossible it is to keep high gloss black clean, but, other than that, zero complaints what so ever.
And, as far as the motherboard goes, absolutely flawless from the moment I started it up! I can overclock this X6 1045 with the ASRock board too(awesome news, I thought the CPU was locked for good), so I'm going to ixnay the FX upgrade plans, invest in some cooling for the X6, and just bump it up a bit. Doing some 3D CAD work and the like, I don't think that I'll need any more than this.

Thanks again for the help, guys! With the way that this hardware is constantly evolving, it was a bit overwhelming trying to pick a motherboard for my specific circumstances, so the assistance is definitely appreciated. Future plans are to upgrade the PSU, swap to an aftermarket CPU cooler, upgrade those two old stock sticks of RAM to probably a matching pair of G.Skill Ripjaws, and to replace the 5770 with an RX460/70. Once I make those changes, I think this will be a solid general use/business system for another 5 or so years.