As others have mentioned, real estate agents do no steer buyers either toward or away from particular neighborhoods. But Boulder County is in general a great place to live. I would suggest you do a little research online and then get into a car a drive around the city. I think you will find that Longmont is a great city.
Prudential Real Estate of the Rockies
From a Realtor's standpoint, we are not allowed to 'steer' clients to one neighborhood or another so that would be a very hard question for us to answer.
However, we can let you know that you can contact the local police department and ask them about crime activity in various neighborhoods. That will get you actual facts that you can then use to decide what areas you would like to move to.
The Longmont Police Dept's website is: http://www.ci.longmont.co.us/police/ and their phone number is: 303 - 651 - 8555
They are located at: 225 Kimbark Street Longmont, CO 80501 Stopping by personally and speaking with the staff their may be your best bet.
Also - when you are considering a house to purchase - you can always google that address and see what newspaper items come up in reference to possible reported activity at that address.
Additionally, driving through various neighborhoods at different times of the day and seeing what kind of feel you get for those areas can be an invaluable use of your time.
Hope this is helpful! Have a great weekend.