the actual parts that you pick for your pc may be a bit different than what i listed above based on price at the time but what i listed is a good enough go-by. i'll list a few preferences here for things that arent obvious:
motherboard: i prefer asus myself but gigabyte, asrock and msi arent bad also.
ram: i prefer mushkin but corsair and gskill are good also.
hard drive: seagate barracuda, samsung spinpoint or western digital caviar black (blue is okay too but less warranty)
ssd: the only ones i trust are samsung and intel. you can use others but not for high-write applications.
psu: anything tier 1,2 or 3. i personally like my corsair HX but seasonic, xfx, some antec and anything in that list are good as well.
cases: i prefer corsair but there are plenty of good brands. cougar impressed me by being sturdy with good features at such a low price.
not the be all end all of lists... but a good starting point.
as for intel vs amd cpus you would think that more cores = better but that just isnt the case in reality. a top of the line fx8350 is somewhat compareable to a i5 but loses on heat (it generates higher heat and has a lower thermal shutdown temp than intel), power (it uses more electricity than intel) and performance (less performance than intel) but it wins out by being slightly cheaper. if you werent adversed to overclocking you could use a fx8320, throw a decent cooler on it and overclock it into or slightly above i5 ranges. my personal choice right now would be intel if its in budget though since they are the leader, however, having an ssd is also a really big thing as well. even with new hardware the pc will still feel like its from 2008 unless you use one.
both amd and nvidia gpus are good. amd is good on performance vs cost typically however prices are a bit out of whack due to bitcoin mining being very good on amd gpus hence the current debacle. the 770 generally beats out the 280x in most tests however is a bit higher priced as well so price/performance is about equal between the two. the 280x however is a bit better in performance for bf4. often its a 50/50 split of games for amd vs nvidia lead performance so there is no one best card.
as for brands... if you go nvidia then asus, gigabyte, evga and msi are decent. if you go amd then sapphire, asus, msi and gigabyte are good.
mantle was developed to share work between the gpu and cpu so if one was stressed and the other was not it would offload some work. i'm not sure how big the gains are at this moment but i heard the same thing that its going to be a big thing in the future. however, dont count nvidia out of the picture yet as its really not a deal killer scenario and wont be unless you have rather mismatched hardware (like a good cpu and bad gpu or vise versa). if you wanted mantle you would need an amd cpu and amd gpu which means no i5.
the issue with the cx600 is not with the wattage. that is fine for an i5 + 770 system (actually its a bit over what is needed which is good). the issue is that there is a single capxon brand capacitor in there which is not a trusted brand and is known to blow. you can read more about it here
http://www.badcaps.net/forum/showthread.php?t=22294 while i'm not sure how it applies across every single CX i do know that they all (all cx models) use non japanese cheap capacitors. now, i have used a cx430 which i bought for $20 in a relatives system but since the actual load was going to be about 150w and their budget was small its really not a huge risk. for a gaming system though its not adviseable and is a ticking timebomb. the corsair HX (i own one) and AX series are very good and i do recommend. basically anything tier 3 and above is considered safe to use.
high heat spreader on ram refers to the metal casing on it. ram without heat spreaders looks just like a green pcb with chips on it. a low heat spreader is just a metal casing on this which doesnt extend much above the pcb. a high heat spreader is one that has a fancy top, fins or some other obstruction which sticks above the ram. while this isnt normally an issue and might actually help with cooling performance on them it can interfere with some cpu heatsinks. while i dont think its a problem with the 212+ i noted it as a just in case thing to check later on.