Skill Points? 99 i think. If you do not spend any of the 99 by the next time you level up, i believe the additional SP are immediately lost. I never made this mistake though so i have never personally tested it. As for perks, you can save any one perk for 2 levels (3 if skilled), but you have to choose that perk before you get the next perk, otherwise you lose it. The last perk however, earned at level 24, can be delayed thru level 29. You have to choose the last perk before you hit level 30.
Someone correct this if it is wrong.