Well, The abortion issue is important, of course, but there is very little a conservative president can do. Best case appoint judges that overturns Roe, since most legislation is challenged under Roe. There is some budget manuvers of course. But the role of the federal government is and should be limited.
However when it comes to the economy the president is amazingly powerful and McCain is a disaster. He is a de facto socialist.
He'll be a far sight better than EITHER Obama or Her Heinous!