On the Traditional vs. Roth IRA issue
The first IRA account I opened was a traditional - I was younger wanted to save, but also wanted the tax credit. Without the credit I would have owed a bit in taxes that year, with the credit I got a nice (not huge) refund on my taxes. At the time the tax credit was the deciding factor.
A few years ago I opened a Roth IRA since the tax credit wasn't important and it's much more flexible (you can withdraw contributions early penalty free in many cases).
An important point is that the traditional IRA gives you a tax
deduction and not a tax
credit. The value of a credit is dollar for dollar (assuming you would owe at least that much tax without the credit, and every credit is different). The value of a deduction is the amount x my marginal tax rate. So if I put $5000 in a traditional IRA and my marginal (not average) tax bracket is 30%, the deduction is worth $1500 and not $5000.
There is also a credit for contributions to any kind of retirement account, but it is only available to people with fairly low incomes.