When I paste with “Paste and Match Style” it pastes the contents of the clipboard depending on what has been there previously (which I have erased but it seems that Scrivener remembers what was used there before). Thus it is not predicatble what font I get when I paste. I usually just want to paste in the default font. Is there some way to do this?
There is no way of doing this, no, as in most circumstances it won’t really be what you (not you personally 
) want to do.
Paste and Match Style - as you note - is the best way of doing this. It will match the current font and style.
Your problem lies here:
When you delete all the text from a text view, the insertion point uses the last font you were typing, which, when you think about it, will usually be desired behaviour. When you click on another document and click back into the empty document, however, the insertion point will be reset to the standard font, so pasting and matching style in that event (or in new documents) will work the way you want and use the standard font as defined in the preferences.
Hope that helps.
Best,
Keith
I get around this issue entirely by using a combination of Quicksilver and a freeware app called Plain Clip. bluem.net/downloads/plain-clip_en/ When I copy of piece of text, I hit a Quicksilver command that uses Plain Clip to wipe the copied text of all formatting. Then I just paste into Scrivener and the pasted text matches the document. Quick and simple and it works the same way no matter what program you’re using.