Personally I would like to see Turkey join EU in a few years, I believe we need them just as much as they need us.
However there ARE still unsolved issues:
*Cyprus is a member of EU but is not (officially) recognized by Turkey, obviously this needs to be solved.
*There are still a lot of human rights issues in Turkey, torture is still common and the democracy is still in its infancy.
*The Kurds are still oppressed in Turkey, they were only recently recognized by the Turkish goverment (before that they were known as "Mountain-Turks" and were not allowed to use their own language).
Within the union the biggest issues are probably:
*Turkey is a big country with a large population, including Turkey WILL be a larger step than including for exampe Croatia (which will start negotiating next year)
*Agriculture. If you look at the EU budget you will see that most of the money is spent on supporting European agriculture, this is VERY expensive and reforms have been very slow. Adding another country with a large agrecultural sector will only make the problem wors. This was/is a also big issue when Poland joined.
*Free movement (aka "They will steal our jobs"). This is actually mainly BS, if you look at the polls you will see that the same people who opposed for example Poland and the Baltic states are know talking about Turkey. In reality it is probably not a big issue, people do not move just like that.
We DO have some problems, so the issue can not simply be ignored (which was a misstake some polticians made, for example in Austria which was one reason why Haider and his fellow nutcases were succesfull). Where I live (Sweden) we have already seen a relatively large increase of people comming from the Baltic states, mainly in construction. Since the salaries are lower it is hard for Swedish companies to compete.
However, it is not a huge problem and can be handled. Besides, the economy in Turkey is improving rapidly so when they eventually join I don't think this will be a big issue.
*Turkey is an important member of NATO and very close the US, this IS a problem for many people who want to see EU as a counterweight to the US. One of the biggest crisis so far in the history of EU was when UK, Spain and Italy supported the invation of Iraq and most of the othey countries did not (Poland was not a member at that time) .
*Xenophobia. Definitly exist and is definitly a reason why some people oppose Turkey joining. However, at least officialy this has not been a big issue (yet). We will know for sure how important this factor is until the results of the referendums in France and (probably) Austria are in (that is in about ten years).
It is important to remember that even "normal" negotiations take several years, so no one knows WHEN Turkey can join. However, I am quite confident that they will join eventually (in about ten years or so).
Personally I would also like to see at least one member from North Africa, but that will not happen any time soon.
Bosnia, Macedonia and maybe even Ukraine are other "obvious" members and should be allowed to join if they want to if you ask me.