I would definitely recommend QuickBooks Simple Start 'cuz your client can send their numbers directly from that program to their accountant at year end for tax purposes. They can also upgrade easily to QB Pro down the road (if they choose to) without having to re-enter all of their data.
I have the QBSS 2010 free version .exe on my computer so feel free to pm me if you can't find it online and I'll send it to you.