I'm going to get a new (used) laptop soon. Which Debian release should I install at this stage of the release cycle, Jessie or Stretch? My current laptop runs Wheezy.

(I want as few bugs as possible, but also dislike the idea of having to upgrade in the near future.)

Also, is Xfce still the lightweight desktop of choice?

@stefanieschulte this is not a choice: you had to use at least a stable version. Most of your wheezy applications don't have security updates.
Updates are the only solution for security.

So you need to use Jessie now and update to Stretch latter. If you only use applications from package you will have security updates and upgrade will be easy.

@yvesago I'm not planning to upgrade from Wheezy to Jessie on my "old-old" laptop, which has very limited memory and disk space anyway. I am planning to retire it instead once I get the newer one in a few days, and I am wondering which release (Jessie or Stretch) I should install on the new machine.
@stefanieschulte stretch is "freezed " so you can use it but you can have some bugs and lot of updates. Take care to change source package to "stable" and not "testing" when Stretch will be released.
Or choose Jessie and make an upgrade in few months.