I did not have to attach anything with my N400, however, I did bring along just about everything there was a mention off:
marriage certificated (req in N400 interview letter)
Wife's Birth Certificate (req in N400 interview letter)
Selective service letter and postcard (req in N400 interview letter)
Kids Birth Ceritificates
IRS TAX summary for the past 5 years (I went to the local office and sweet talked to a lady and she printed for me free copies, otherwise you have to pay $29 for each year via mail in request)
Naturally: my GC, Passport (expired, but it did not make any difference since I did not travel) with I90 (white card I think it called)
my tranlsated Birth Certificate
my pay stubs from work (I had like random ones from the past 2 years)
Insurance cards(health, dental, vision, prescription) showing I was a policy holder for the entire family.
Social Security card (req in N400 interview letter)
Driver's License (req in N400 interview letter)
both mine and my wife's
I contemplated on bringin pictures with, but figured if he/she(officer) really want to see them I would just give them my website address and they can go thru all 2300+ hi res images I host on it

accumilated in/for the past 8 years.
Oh, letter asked for a Divorce Decree either me or my wife, well, it is a first marriage for me and 2nd for my (USC at birth) wife, so we got that rounded up.
basically most of the documents you need are the same from your AOS app. I just brought a check book (which has not been used in almost 2 years, since I bank online and we use check cards or credit cards) showing both of our names, utility bills with both of our names, Credit card statements.
In my case, officer asked for the last years taxes and forms - I gave it to him, he saw that we file joint return, same address for the past 8 years, we own the house (I brought few mortgage payment coupons).
I did bring letters from friends and relatives describing my good moral character, but it never came to it.
Truth to the matter: I support family of 6 including myself, my wife is a stay at home mom (with job much harder than mine, by the way), I am a sole source of income, insurance and etc. Lack of US citizenship did not restrict me in any other way other than inability to cast my vote against GWB during this last election or travel on a fly, although it is almost impossible with my line of work - I am an engineer for SBC Global (big Telco) and am responsible for all critical equipment and maintenace of it for a population of about 150K. I am on call 24/7 because very few people can support or know anything about multi million dollar equipment SBC has been purchasing for years, I get shipped all over state of WI.
I did have a 0.05% chance I would have been denied citizenship if officer wanted to be really ****, but It went smooth (little longer than anticipated wait for clearance checks - and NO, my family is the ONLY one in US with a unique last name such as mine so nothing common there

)
I had wonderful attorney helping me thrughout my quest - yes it is a price of a nice used car, but in my mind -- well worth it. If you have money go for it. One of my fraternity brothers' recommended me attorney firm in Milwaukee I went for it and do not look back at all - I did not have to do $hit, othen than gather and ship documents. FedEX made a lot of money off us

but again, sure beats 2 hour drive each way to Milwaukee. I did fill out N400 on my own (was not that hard) and my attorney told me there was no reason for him to go to the n400 interview and he was right - oddly, he actually saved me buch of money about $1000 for N400 and presence at the interview. Everybody needing immigration legal help in WI who I ever talked to I recommend him without thinking twice about it.