If you are working with a real estate agent that you trust and are satisfied with I think they can be one of your best resources for a lender/broker referral. They have a vested interest in seeing you get approved quickly and efficiently and may have a relationship with the lender that will bring you a better level of service. Certainly call a few people, ask friends, your attorney; but under no circumstances would I just "cold call" a lender. Chase may be a great bank to apply to, but every loan officer there will be different, some will excel some will just plain stink. In just the last two weeks I have seen two clients grow frustrated with their mortgage broker whom in one case may have cost the buyer a deal.
Be proactive and get someone good from the start!