I am perfectly qualified to not use an accountant. I am a business professor, and my work crosses over into accounting quite a bit. I would certainly find a CPA that is reputable and hire them for advice before starting. I know a physicist who didn't do that and found they ended up with $78,000 in fines.
There are a number of specific things an accountant might provide that Quickbooks will not. First and foremost, they are an outsider's set of eyes. If they are good, they will find a polite way to say "you want to do what?!?!?!" If they are good, they won't fall out of their chair, their jaw won't drop to the floor, and they won't giggle until they get home.
A good accountant has seen around a hundred successful and unsuccessful businesses. They have seen everything you may have thought of. Intelligence is learning from your own mistakes, wisdom is learning from the mistakes of others. Accountants are the repositories of wisdom.
An accountant can point out weaknesses in your plan and help you shore it up. They can provide information about the local market that you may not be aware of. They can assist you with understanding the long run consequences of the legal form that you choose. They can assist you in understanding the trade-offs of different funding models. They can also do tasks that you are not talented at and which will take a lot of time if you do it, and little time if they do it.
There is a reason that accountants are required to have 160 semester hours to sit for the CPA. They also have to have a few thousand field hours before they can sit for it as well.
There is one thing you may want to keep in mind though. An accountant will often do what you ask them to do, so think about what you want before you visit the accountant. Also, remember to ask the question "is there a question I should have asked but didn't?"