I live in Utah, Zone 6b. I've read on some websites that is is perennial, others that it is not. Just planted some in my mini greenhouse, I'm hoping that it is :)
I think it depends on whether you intend to keep it outdoors or not.
I LOVE lavender - and every year I plant some in my garden. I noticed some came back the next year, and some didn't. But, none of my lavendar came back for the third year. That said, I decided to keep some lavender in a pot and keep it inside - she seems to be doing really well as an indoor plant.
I wish I could help with variety name, but we live in zone 5 and successfully grow Lavender as a garden perennial. There are a few types, and most seem to be a bit too tender to tolerate the colder winters... but there is one commonly sold type that will survive. I grew some from seed sold at our local farm type store, so I know it must be a common variety.
The fancier types don't usually survive, but you can grow the more common type as a hardy perennial. Look for seed to start at your local stores when vegetable and flower seeds are offered for sale. It will probably be located with the herbs or perennial seed.