I strongly recommend "Arrid Deodorant Cream." It comes in a small jar and you spread it on with your fingers. I had problems with regular deodorants and started looking for alternatives. I tried the natural versions - Tom's and various alum-based (crystal/rock) alternatives. They were all very ineffective for me.

The Arrid cream does not cake or flake, does not contain alcohol, and is extremely effective for me, and trust me, I need a strong deodorant. I have had to irritation or itching. I almost felt feminine using it (it has a baby-power type smell) but trust me, it has some muscle. Give it a week to get used to it.

The nice thing about the cream is that it can easily be transferred to other containers. I travel a lot, and I have a very small makeup container that I use for overnights and a smaller squeeze jar that I use for multi-week trips. It comes in a small jar packaged in a square box:

Arrid Deodorant Cream at Walgreen's