Smart to roll 401k from previous job into new one?

NO. Roll it into an IRA.

No. Put it into an IRA. WAY more choices on how to invest your money.

Also, it will not go against your IRA contributions if you roll it into a designated Rollover IRA. The contribution limits apply to Traditional and Roth IRAs.

I'll be the dissenter and say don't roll into an IRA. Sure you'll have more choices, but are you a professional? If not, I'd guess you'll end up paying higher fees and increase the chance you're going to do something stupid. Unless you have high confidence in your ability to manage your money, leaving it in a qualified plan in something like a target date fund, will likely result in lower fees and a better outcome than what you'd realize on your own in an IRA.