One thing that you have to remember when dealing with tax deductions is that tax deductions are not a way to save money dollar-for-dollar! That is, money spent on gear, travel, etc, or ANY 'business expense', does *not* equal tax savings dollar-for-dollar. Deductions only reduce your *taxable income*, which in turn reduces your taxes by a percentage - but the amount of money spent on a deductable expense does not equal the money saved on taxes.
I know the following numbers may vary greatly from person to person, but just for the sake of example: For instance, let's say you make $30,000 a year. With no deductions, your taxes (state and federal) may be roughly $8,000, assuming a total income tax of 26%. Now - you want that new Canon 20D and a VX2100, with L-series lenses, wide angle adapters, tripods, software, tapes, memory cards and accessories for a total of roughly $7,000. If you established a legit chasing business and deducted these items as expenses, your deduction would be $7,000 (if you deducted the full amount in one year rather than opting to depreciate the items over multiple years). Now, that $7K does not reduce your $8K tax bill to $1,000. What it does is reduce your taxable income by $7,000, so now your taxable income with the deductions is $23,000 ($30K income minus the $7K deduction). This only reduces your taxes to $5980 from $8,000, a tax savings of only $2020. In other words, you still have to pay taxes on the $23K. So, you spent $7,000 on gear and saved only $2020 on taxes.
In order to reduce your $8,000 tax bill to zero, you would need to have zero taxable income. This means you'll need to have deductions (expenses) that match your *total* income, which in this case would be $30,000! So, to pay zero taxes on a $30K income, you'd need to SPEND $30,000 - all to save just $8,000 on taxes! This won't work for two reasons - First, as mentioned in previous posts, the IRS is not going to allow you to do this for very long. And secondly, if you made $30,000 and spent $30,000, obviously that leaves you with absolutely no money to live on for that year!
In other words, justifying a large purchase or ANY expense by saying it is a tax deduction does not end up saving you as much money in the end as you think. Buying that new camera will still cost you a large sum even after the tax deduction. If you really need the equipment, that's one thing, but if the sole reason you're getting the gear is for the tax deduction, it won't help you as much as it may seem.
When you have a business, a lot of people (insurance companies, salesmen, etc.) will try to ease the pain of expensive items, rates or fees by touting the tax deduction you can take if you bought it. But just remember tax deduction =/ direct savings on taxes.
I guess my point is, don't fall for the trap of spending a large sum of money on expenses just for the tax deduction. Unless you really need the gear, it's actually cheaper to just pay Uncle Sam than try spending money to reduce your taxes.
As you mentioned intent, by doing so and if there are mistakes, I can guarantee you the IRS will be much more forgiving because you were acting under the advice of counsel. And, besides, you can write off your tax attorney fees too! 
