Based on current polling, I am confident that Biden gets to 278 EVs *in the absence of republican fuckery* by holding all the Hillary states and winning back MI, WI, and PA. I'd expect that he wins those back due to regression to the mean alone. They'll drag out PA of course, but I don't think the outcome will be significantly in doubt.
I am fairly confident Biden wins NE-2 to bring him to 279. I'm not quite comfortable calling ME-2 for him, but think his chances are decent.
I am leaning toward him winning at least one of AZ, NC, or FL (in order of most-least confidence). I believe Florida is a true toss-up. They elected a republican governor and senator during a wave year which doesn't bode well, but the aggregate polling has consistently favored Biden. So who knows. I'm slightly more bullish on NC and AZ, but only slightly. But if any of these 3 are called for Biden by the end of the night, you can more than likely pop the champagne.
I think GA will be close but ultimately tilt toward Trump, maybe by 1-1.5%.
TX will be closer than in years past, but ultimately think Trump takes it by 2-4% (if not more).
I'm mildly worried about MN and NV. I would be surprised if Biden lost either, but don't think it's out of the realm of possibility.
I'm also mildly worried about an electoral college tie (nightmare scenario). Unlikely, but could happen by Biden losing PA, NE-2 and ME-2 but winning AZ, or splitting NE-2 and ME-2 but losing WI or MN, or NV and NH. I will breathe a huge sigh of relief if it's announced that ME-2 and NE-2 are both won by Biden. However, if the EV margin is 270-268, I will be shitting my pants over faithless electors.
Overall, I think 279 EVs for Biden is the most likely outcome. Close but somewhat comfortable, with up to 335 if things go better than expected. Hoping for a blowout of course, but I'm generally pessimistic.