asus boards are the finest out for stability and mild to medium o/clocking.3yr warranty and quick replacement if you do get a bad board.
If i were you i would but the asus a8n-e ultra board,it gives you the sata2 option.the a8n5x is the same board but without sata2 and the options that go with the ultra chip.
i went through 3 other ultra boards before buying the asus and what a great board it is.fo instance the layout is perfect,it has mature bios,its stable as a rock,o/clocks surprisingly well and and is as close to a perfect board in function and design as possible.it never crashes,never had a blue screen of death.the only thing ive done is made a modified chipset cooler with the zalman n47 heatsink and put a 10x40mm led fan on it[cost 12.00 total]and its amazing performance really pleases me.im running a 3200 venice e3 @ 2550mhz with 1.375v and corsair xms3200c2 ram @2.5,3,3,7 1T running 1 to 1 with the cpu.its a fast setup and runs cool.I make my living building computers and this setup is the finest rig ive had in many years.it would take alot to get me to get rid of this setup and upgrade to something else.
Now if your not sold on asus ill tell you about some other boards ive built systems on that impressed me.the biostar tforce ultra and sli boards are awsome.i like the tforce sli board alot.many o/clocking options in bios,like dfi kinda.comes with alot of extras too.
the abit kn8 ultra was a good board but layout sucks and its ram picky too moreso than the asus.the asus a8n sli vanilla version and the asus a8nsli premium kick butt boards.dfi ultra d if you know what your doing and have all high end reccomended hardware,very picky board but for max o/clocks its the cats ass.the final board i liked alot is the msi ultra platinum,nice layout and firewire onboard was expensive now like 109.00 or something on newegg.so these should give you something to look at and i know from experience these boards are very good.look around and see which one is the best deal.i know the msi board sold for about 145.00 dollars for a long time and now its cheap in comparison.lots of features with it too.
honestly though my favorite is the asus a8n-e and alot of my customers ask me what would you use if it were your computer.ive built over 20 computers with the a8n-e board and never had a bad board and to this day not 1 failure.same goes for the a8n sli vanilla board no bad ones and no failures.cant beat those odds.had 1 doa biostar and has 2 msi boards fail within 2 months.but all companies will have a bad board go out and its just the law of averages..i dont hold it against any mobo manufacturer,it happens to all of them...........