I love Wiltshire. Just about the best place to live. But there are pockets of good and bad. Personally, I wouldn't live in Trowbridge, but I do get my groceries there! (a 24-hour super Tesco).
Bath has a good train station and it's near city centre. (A bus is a good option, too.) My opinion would be to find something that has good train connections to both Salisbury and Bath. Parking is abysmal in Bath.
We've (my husband and I) have chosen to set up our own business in Melksham. We could be anywhere, and in our business, you wouldn't think Melksham was a good spot. That's why we keep doing sanity checks. But we love it here and we're not that far from London (not more than 2 hours by either car or train or bus). And very central to a lot of other areas. It's also gorgeous countryside. The people are great; services great.
From Melksham, I can get to Bath in less than 45 minutes on an hourly bus service. Bristol is best reached by car on the M4, and I can get there in an hour. Salisbury takes about an hour by car. Bristol airport is about an hour, Heathrow is a little less than 2 hours. Oxford, about an hour. Cardiff, a little over an hour.
Any more you can tell us? Where your work is?