Good suggestion, I’ve added a poll, open for 3 days
However before you record your guess, remember that we don't have national elections in the United States. All elections, even for federal offices such as president and vice president, and for members of the national Senate and the House of Representatives, are conducted by the states. And those who will serve as president and vice president are, uniquely, decided by state-by-state assignment of "electoral votes"
a mechanism, roughly based on proportional representation, by which the states select among the competing candidates
after the election has been conducted based on the votes cast by their respective residents.
Joe Biden is all but certain to win the popular vote, just as Hillary Clinton did in 2016. Based on the publicly available survey data, he probably will win the electoral vote as well, but I wouldn't count Trump out yet. An important factor is likely to be voter "turnout"―the ability of the two candidates, and the parties and interest groups supporting them, to persuade their supporters actually to vote. High turnout probably works to the advantage of Democratic Party candidates, but the Democrats historically have had difficulty getting certain demographic groups that tend to favor them to vote, particularly young people. And a number of states with Republican-controlled governments have been engaged in extraordinary efforts, most of them presumptively legal, to depress voter turnout.
And, again, the national vote totals won't determine the outcome; the state elections will. For those inclined to stay up all night (here in North America) or get up very early (on the other side of the Atlantic)―those of you Down Under should have it relatively easy―I would recommend watching two states: Florida and Texas. Both start counting early votes (such as mail-in ballots) before election day and both are therefore likely to be able to report their results ahead of many of the other so-called "battleground" states.
If Trump loses one of them, he still arguably could assemble a winning electoral vote, but it's unlikely. If he should lose both, it's all but impossible to imagine any way he could be re-elected. The current survey data indicate Biden and Trump are very close in both states, with Biden having a probable advantage in Florida and Trump in Texas. I'm still skeptical about Biden's chances of prevailing in the latter, but the polls suggest it is possible and it's no coincidence that Michael Bloomberg, the billionaire former Democratic candidate, has decided to invest significant advertising money to defeat Trump in both states. (Bloomberg also decided at the last minute to invest in Ohio, another state that would normally be considered a certain winner for the Republican and a "must-win" state for Trump.)
So record your guess in the poll above, if you like, but keep in mind that while Trump started and is ending his term in office with unusually low national popularity, state-by-state support is what will actually determine the outcome.