What is a good cell phone to use to check and send business e-mails while I'm on the road?

I am buying a new phone which will be used mainly for business. I was looking at the Samsung SCH-u740 since it has a keyboard. The i-phone is too pricey and I'm stuck already in a 2 year contract with another phone company. I definitely want a phone with a keyboard since I will need to send documents with changes made to them. What is a phone that would allow me to download Adobe Acrobat in it? And it absolutely has to have Windows capability for my documents. Also, I noticed some cell phones have "Mobile Web 2.0" and others have Windows Mobile 5.0 OS -- what is the difference between these 2?

check if ur phone company supports blackberry .. the blackberry pearl is very good...