We're starting early on our research for a twin bed. Buy something well-built and it will last until college. We think the Perspective twin bed from Room and Board fits the bill.
It's great looking -- substantial and simple hollow squares make up the footboard, headboard and legs. The entire bed frame is made of steel with a natural finish. Like many modern beds, the Perspective only takes a mattress (no box spring necessary).
You'll be glad to know the Perspective also comes in full, queen and king sizes.