The benefits within your IRA will pass directly to your named beneficiaries without being subject to the estate probate process.

Investments in a traditional IRA or 401(k) retain most of their character as an IRA or 401(k), but they generally must be withdrawn from those accounts over time. The timing of withdrawals depends on whether your spouse inherits it or another beneficiary (such as your child). 
If your primary beneficiary is your spouse, he/she has the option of "assuming" the IRA (taking over ownership). This option could continue to defer taxes on the IRA even longer. Any other recipient has to take distributions based on either a five-year timeline or his/her expected lifespan.