also i think ill add… avoid Hitachi drives in general in your XBox360 as there generally considered junk by most of the experts i talk to plus if you want to mod your system… the Hitachi drives are easier to brick (i.e. permanently kill) vs the other drives like Samsung/BenQ/Liteon which i have moded all three of those and there pretty easy. i never moded a Hitachi before myself though.
to sum it up the best drives are…
1.Liteon (with a close 2nd to…
2.BenQ (in general… if you buying a replacement drive for your XBox360, this is the one to get)
3.Samsung (i have a Samsung MS28 myself)
4.Hitachi v78/v79
(big gap here)
5.all other Hitachi’s
360 Drive Models - http://tinyurl.com/6hpktl … that’s a simple way to tell the basic drive model you got in your XBox360 without opening the case as all it requires is removing the face plate (which simply just snaps off) and looking inside a hole for the wire color etc… pretty easy 
but anyways back on topic… i had my current XBox360 (which i got used) since April 2007 and it’s not RRoD yet but i been using a Nyko Intercooler EX on it pretty much as soon as i got it and it keeps the side of the XBox360 case noticeably cooler to the touch so i would assume it must be helping the system in the long run but there is no proof that it does and some people claim there bad for the system etc etc… either way avoid the early model ones (i.e. the ones that come in the plastic box vs the cardboard) as they actually have melted to the system etc etc (there is pics online of this happening if you look around)
but i do notice my system has a small glitch (which it’s been doing since the day i bought it) … when the system is cold (like been sitting for hours to where it’s completely cool) and i first power it on, nothing will display on the tv at all but usually if i power it back off (after leaving it on for about 20seconds or so) then turn it back on it works and once it works it’s been quite stable as i rarely get freezes in games and the system’s been pretty good on the whole… so it must be something to do with HEAT that makes it work
p.s. i totally agree with Jedi Master Yoda as the original XBox’s where much more reliable in general and had a much much lower failure rate, especially as far as major system failure. the XBox360 is just a flawed design and most likely wont be properly fixed in the life cycle of the system. so lets hope the generation of consoles from Microsoft will be more reliable like how the XBox1’s where.