Is it a great time now to convert traditional IRA to roth?

Lowkey,
Certainly, with the market down the cost of completing a Roth conversion is reduced simply because the account value of the IRA is reduced.

In the end, though, it's still only good to do a Roth conversion if the other factors for it are in your favor. Overwhelmingly, the top two factors (in order of importance) to having a beneficial Roth conversion are:
1) Tax rates. If your tax rate NOW (during conversion) will be lower than your tax rate in the future when you will ultimately be withdrawing the IRA funds, conversion is favored. Of course, this will be somewhat hypothetical (since we don't KNOW what your future tax rate will be) so you'll need to estimate as best you can based on your situation.
2) Outside money. If you have available funds outside of your retirement accounts to pay the tax on the conversion, it enhances the success of your Roth conversion.

With currently reduced account values, you'll find that it's a great time to convert, IF the above factors are in your favor. If they're not, though, then a Roth conversion still won't be a win for you.

I hope that helps a little!