Decisons for my Birthday

For my birthday, my mom kept insisting that she wanted to get me a present before she goes on vacation. Unfortunately, she won't be able to give me my present on my birthday, but she wants to get me something. Rather than buying me something, she wants me to tell her what I want and she'll get it (of course within a reasonable price - I'm not going to take advantage of my mom's generosity).

Anyways, I thought long and hard about what to tell her, and I thought this would be a great time to ask for an accessory for my T2i.

I already have the following:
1) T2i (duh)
2) 18-55mm kit lens
3) 55-250mm lens
4) camera backpack

The choices I narrowed it down to include:
1) external flash (SpeedLite 270 EX or SpeedLite 270 EXII)
2) EF 50mm f 1.8 II lens (the cheapie $100 one)
3) Canon battery grip

What do you guys suggest? What other accessories would you recommend?

--
Imagination is the key