You are unable to return to Pre-Searing Ascalon after entering the Academy. Use of this checklist will make sure you get all that is needed, before you leave. Almost everything can be obtained later, but it usually is more expensive.
Belt Pouch traded from Brownlow or Humphreys
Tapestry Shred from Gwen Cannot be obtained later! (This item is used for a quest in the Eye of the North expansion)
Charr Bag from Charr bosses north of the wall. They are dropped as a green item and hold up to 10 items.
50 gold for Storage Chest
Starter Armor (if your primary profession is a monk, you can use this for 600/Smite farming)
Once you have chosen your Secondary Profession, complete the quests available to you (limited by your primary and secondary professions) for an easy way to get some basic skills and experience. It is also beneficial to complete all available secondary profession quests before deciding on a final choice, as this will give you valuable experience towards leveling up.