Well 1st off, the decade drawn line is not a hard line; it's more of a fuzzy math. And IMHO once your on the helmet list "double digit win" seasons is needed to be consider to perform at helmet level (10 win seasons doesn't get you on the list, but will keep you there.)
Keeping them high on my list even with current non-helmet performances:
Texas - 2 great seasons and a natty in the last decade, if Hermon bombs out they slid on my list.
USC - 4 Rose Bowl Wins in the last decade.
Sliding down on my Prestige list:
7-10 - Helmets in my book, but not performing as well as the teams above them. Meat-chicken under Harbaugh is right there, but not winning against OSU, repeat 3rd place Big Ten East finishes, and losing their only "Big" bowl, says they have not returned to the mountain top.
Notre Dame - Haven't performed at helmet since Lou Holtz circa '93. Personally I think their 2012 season was lucky and getting crushed by Alabama confirmed that for me.
Slipped off my Helmet list:
Nebraska - Solich had a couple great years ... last millennium.
Tennessee - Fulmer won them a natty ... last millennium.
Miami - Amazing 20 year run ... in the Big East, haven't been a contender for 15 years of ACC.