I can't tell you if you should get the vaccine because I don't know your dog or lifestyle. It is not a major problem in Texas (compared to other areas). It is a very big problem here in Michigan and Ellie's vet office recommends it for all dogs. This isn't not a good policy though. Ellie had a serious reaction to it (common in Yorkies) and I could've lost her. Some vets won't give it to dogs less than 10 pounds. This is between you and your vet but I would look at how big of a problem the disease is in Texas, if you live on a farm and if you live by slow moving water (where bacteria thrives).
By the way, you are probably more likely to get lepto if you work around water or anywhere where rats urinate rather than from a pet. While getting lepto from your dog is possible, it is a very low risk. Also, some vet schools are wising up and won't vaccinate against this (or only in unique cases).
http://www.petresource.com/Articles%.../texas_vet.htm