Motherboard to unlock Phenom II 555BE?

Unlocking two stable cores is not a done deal. If you need four cores, buy four cores. That said, I unlocked a 4th core on a 720BE using an ASRock mobo. I thought I read somewhere that they (ASRock) had resisted AMD's desire for a BIOS fix to prevent unlocking; unsure if that is still of any significance.
For a single HD5770, even with a high OC, you won't need anything more than 500W-550W. Choose a PSU with a modern design featuring full range active PFC (no little voltage switch) and 80+ certification. Antec, Corsair, PC Power & Cooling, Seasonic, and Enermax are among the better brands. If I were buying, I'd choose a 500W Earthwatts on a tight budget, or a 550W Truepower New (both from Antec) if I could spend a little more. Either are 80+ bronze.
If, however, you might Crossfire with a second HD5770 in the future, you'll want 650W-750W. Truepower New is available in that size. If you go for highest possible efficiency, check out Seasonic X-650, which is 80+ gold certified.

As jtt said don't get the 555 wxpecting to be able to unlock the extra cores as there are many of the chips that do actually have defective cores and will not be unlockable so buying it with that expectation is setting yourself up for a let down. - THat siad I've got a X3 720 with an unlocked 4th core that runs fine on a Gigiabyte MOBO (just need to make a couple BIOS changes to enable the core unlock -- First change the EC Firmware Selection to HYBRID and then enable ACC ) and if the cores are good the system will still post and run windows - if not then you just go back into the BIOS after it resets itself when the boot doesn't work and disable them again - so doesn't hurt to try - just remember it is not a sure thing and also you will want an aftermarket cooler as if it does work the chip will be running alot more power through it than the stock heatsink was designed to handle so will run much hotter if you use the stock heatsink.

Thank you everyone for your replies.

So I guess I'm done with the PSU problem. 450W.
And almost coming to a conclusion with the RAM, that 1333 should suffice. Someone disagrees?

Am still learning about the Mobo. This link helped a lot, though could use some more help! I'd appreciate if people can please name specific board models, so that I can see what are people recommending the most. That would definitely help me with my decision. It must not have many bells and whistles, as long as it can unlock and OC to a little 3.6GHz, I'm fine with it. The lesser the cost, the better!

Thank you again everyone for your replies :-)

Some of the quotes below are taken from different forums!

Thank You, I understand that. Though I'm willing to gamble!

Thanks. I've used that and found that my Recommended Minimum PSU Wattage is 379W, so I think I'd go with a 450W PSU.

I'll go with 450W

So will a 1333MHz RAM be fine? I'll check the prices, if the difference is negligible, then I'll go with 1600MHz. But if there is difference in performance, then I'll go with 1600MHz only!

If a board has a BIOS that doesn't support unlocking, can I change the BIOS?

OK after going through all the suggestions (thanks for it), I think that Asus M4A785TD-V EVO $100 is the motherboard that will suit me. Since I'm not gaming, I've decided to save $200 by removing HD 5770 GPU. And since the mobo has IGP HD 4200 with 128MB shared, expandable to 512MB shared, so it should be able to play videos at 1920x1080 res(?) Anyone has experience with this mobo? And how are Asus mobos in general? Are they worth a buy?

The other contender here is Gigabyte GA-MA785GT-UD3H $95, the only difference I can see is that it has just one PCIe slot, which is why I'm giving Asus a preference. Rest its the same.

But I need a go-ahead from someone knowledgeable! Should I press the button for Asus M4A785TD-V EVO or does anyone has a better (in terms of price and/or features) mobo? It should be able to unlock cores, OC to 3.6GHz and have an onboard video.

How would I know if its having lower times, high mem bandwidth and tight timings? What do I look into to find it? I've seen something like 9-9-9-9
Is this how you identify it? So what digits should I look for? They must not be very costly! Best-bang-for-buck will be good enough for me.

ASUS is a great MOBO but heres what recently decided on... I've heard these Gigabytes are built strong and great boards and great success at unlocking the other 2 cores on this exact same chip (x2 555 BE) below is what I got but the mother board you have listed was my second choice buy because I wanted the USB 3.0 and SATA 3.0 for future proof and I wanted to buy a gaming graphics card but since your not really gaming you can utilize the onboard gpu and be fine. Not too familiar with the tech terms on the memory but I did alot of research and it seems the G.Skill 4GB package is the way to go with this board and cpu. Anyways take my advice for what it's worth I was trying to keep myself on the lower budget too but ended up with that package at about a little over $600 but you don't need everything I have listed below: oh yeah and your fine with 1 pcie slot unless you plan on running 2 gpu's in crossfire...

G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Dual Channel Kit Desktop Memory Model F3-12800CL9D-4GBNQ - Retail58206198 (N82E16820231193) 58206198 3/12/2010

AMD Phenom II X2 555 Callisto 3.2GHz Socket AM3 80W Dual-Core Desktop Processor - C3 Revision Model HDZ555WFGMBOX - Retail58206198 (N82E16819103846) 58206198 3/12/2010

XFX P1-650X-CAG9 650W ATX12V 2.2 / ESP12V 2.91 SLI Ready CrossFire Ready 80 PLUS BRONZE Certified Modular Active PFC Power Supply - Retail58206198 (N82E16817207002) 58206198 3/12/2010

XFX HD-577A-ZNDC Radeon HD 5770 XXX Edition 1GB 128-bit DDR5 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card - Retail58206198 (N82E16814150464) 58206198 3/12/2010

GIGABYTE GA-790XTA-UD4 AM3 AMD 790X SATA 6Gb/s USB 3.0 ATX AMD Motherboard - Retail58206198 (N82E16813128416) 58206198 3/12/2010

HEC 63RABB Black Steel ATX Mid Tower Computer Case - OEM58206198 (N82E16811121098) 58206198 3/12/2010