Expiring student visa / re-entry as visitor.

Hello all,
I apologize if this question has come up before, I did look through the forum but didn't see anything.  I'm currently in the UK on a student visa which will expire on October 31st.  I'm taking an interruption in my PhD and will be going back to the states.  I wanted to visit some friends in Germany for Halloween, so my plan is to leave the UK before my visa expires, come back to the UK as a visitor, then fly out to New York a week or so later.  My question is, will I have any trouble coming back in as a visitor?  As I say, it will only be for a week or so, and I'll have a one-way ticket to NY in my possession.  I just want to make sure everything remains above-board, as I will have to eventually come back to the UK for my viva, and may apply for a Post-Study Work Visa later.
Thanks!

There is nothing to prevent you from re-entering as a visitor once you have had a residence visa expire.  Just realise (as you are kind of hinting at) that the IO will need to be convinced that you are truly a visitor and not trying to "sneak" back in.  A clear itenerary and a ticket back to the US should be sufficient.  Also knowing specifically where you are going to stay for your week and potentially having some evidence that you have a life in the US that you need to return to would be a good idea just in case you get a grumpy IO.

But the best rule of thumb is to only answer the questions asked and only offer up what you are asked for.  Plopping a big pile of paperwork at the IO and talking a mile a minute about how you are only visiting will send of red alarms quicker then being un-prepared.

Will re-entering on a visitor visa present a problem in the future if she then applies for PSW visa?  I seem to remember a discussion about this a while back, but don't remember the outcome and can't currently find the thread.

Someone did state that it is only for in-country applications that the last leave had to be as a student. For out of country it apparently doesn't matter.

Yes, you can't switch in country from a visitor to a PSW, basically you cannot switch from a visitor to anything.  They have been doing their best to close off any means someone can switch from a vistor to a resident.  But you can always leave the UK and apply for a PSW.