If you have bigger plans(long term), with that forum then go for vb.
If you use nulled script eventualy you will get reported or their prath team will find you.
If you don't want to invest in that go for phpbb, smf, mybb, etc. anything that is actual today.
Me personaly if on budget will use phpbb, because they have many plugins and some support, others come ond go...
But if you are on the budget, then I will suggest to start with the WP blog,
then if you get enough visitors and subscribers go for free forum script like phpbb, if that goes well, then buy VB and make import from phpbb.
Thanks Nemanja, you are great. I was really thinking the same thing but a bit confused. You make me clear about it. You have provide a real and simple strategy: