I would recommend, without additional information, the 550 Blackee.
In fact, I would only recommend the 550.
but I am not a fan of asrock mobos - which does not mean it's bad either. just my preferences are for Gigabyte, Asus, MSI. and some biostar boards
if you are building a new system, and buying all new parts, get all AM3 parts
The 550 is an AM3 cpu. However, AM3 cpu's are backwards compatible to socket AM2+ mobos. AND I would be willing to bet the asrock has an AM2+ socket on it.
AM3 socket requires DDR3 ram.
AM2+ socket requires DDR2 ram. (that's the indicator)
and the 550 Ph II cpu will work in either socket and will use either ram - cos it has a dual IMC = internal memory controller.
ddr3 might be more expensive; but if it's not much more, get an AM3 Socket motherboard, which means forget this combo if it's AM2+
DDR3 will bring about 5% performance increase.
but the real story is that everything future from AMD will all be AM3. So all the new cpu's that are and will be rolling out now thru end of 2010 will ALL BE AM3. and that means you have an ongoing parade of possible upgrades for your AM3 mobo.
however, that is also true for AM2+ MOBOS. due to the back compat. of AM3 cpu's being able to work in AM2+
THIS might seem confusing.
The big difference is that all the new motherboards will be also socket AM3 MOBOS; so it you want a new mobo in a year or so, AND if you bought an AM2+ cpu, you could NOT use the cpu in ANY of the new mobos. this is simply the rest of the picture.
Personally since DDR3 has gone cheaper, in most places in the world, I recommend getting DDR3, an AM3 mobo and AM3 cpu.
I don't like asrock because they describe their stuff as am3 mobo simply cos it will use the back compatibility idea - most I have seen have a SOCKET which is AM2+ - and that's the kind of stuff that is likely to appear as a combo deal. - altho not always.
I hope this helps. It really comes down to the price of ddr3 vs ddr2.
Having said all that, and outlined the entire upgrade path, which can be confusing, the bottom line is about price. But the best thing is that you and others can make an educated decision. Think about it.
The prices don't look quite right to me. According to the comparison here: http://www.anandtech.com/bench/default.aspx?p=97&p2=87
(they have the e7500 but not the e7400), the two should be a lot closer in price. They trade benchmark wins.
Consider also, if you care, the e7400 will not support WinXP mode in Windows7, the 550BE will.
I have that particular ASRock board. It is AM2+. It has been rock solid since I started it up, I think back in February. It has run almost 24/7, with down time limited to an hour or so here or there for a hard drive upgrade, addition of a discrete GPU, and some spare component testing.
Do you have any other CPU options, possibly as upgrades down the road? If not, get the 550BE (unless a particularly important-to-you benchmark strongly favors the e7400). If so, and if getting something like an e8500 or Q9400 is possible, get the Intel board, as performance should be better.
sorry for having such a slow response to your guys awesome comments!i had to go somewhere, anyway ive been doing some research and i think the e7400 with a p5q pro $401.10 NZD as this mobo has some awesome features and asrock's offering isnt as attractive. i also hear the p5q pro is great for overclocking. about the i7, a little out of my price range lol. the main dissatraction to the phenom is that there arent many decent mobos here for it otherwise it looks like a great cpu also AM3 boards are a bit expensive and so is ddr3 for my budget. i want to make full use of the cpu. i also think new zealand is intel country lol maybe cos of something gov. related i dunno