OK, well allow me to rather STRONGLY disagree with the consensus here. Hillary will not be impeached, no matter who controls Congress. There are two reasons for this: legal and political:
Legal Republicans investigated Bill Clinton for 6 years and found nothing they could use, despite the fact that they really didn't like him. Then came Monica Lewinsky. Because she was smart enough (or strange enough) to save a dress with Bill's semen on it, Bill was PROVEN to have lied under oath. That and ONLY that allowed Congress to vote for impeachment. Monica's word would never have been enough. Suspicion of Bill Clinton over a variety of issues starting with Whitewater would never have been enough. For that impeachment to happen, Bill had to lie under oath and it had to be proven beyond a reasonable doubt.
In the only other example of a Presidential impeachment, Andrew Johnson fired Edward Stanton, the Secretary of War. This violated the Tenure of Office Act (itself unconstitutional) which attempted to restrict Johnson's ability to fire Lincoln's cabinet members. So once again Congress had an action by the President which was crystal clear.
In Hillary's case, even if you believe she is guilty of criminal activity, it's very murky at best. It's also very confusing to the public. We're not talking about covering up a Watergate break-in here. You would have to prove beyond a reasonable doubt that she deliberately used a private server in order to hide secrets from the public. IMO, they never will.
Political Beyond the legal aspect is the memory that the impeachment of Bill Clinton only increased his popularity and decreased the popularity of the Republicans who voted to impeach him. Like government shutdowns, that lesson was learned by Republicans. They're not going down this road again. In fact, I strongly suspect that no matter what they claim now, once Hillary is elected they're going to try to work with her as much as possible, because it's pretty clear that bipartisanship is what the majority of the public desires.