Simon Kjaer from Wolfsburg. I got him fo £19M in my second season and he's awesome.
Also Holger Badstuber from Bayern Munich. He has a price of £4.5M but I'm sure you will have to pay quite a lot more for him (£15M - £20M) but he's class. He can also play on the left.
Finaly Toby Alderweireld from Ajax is also brilliant, very young, has great stats and world class poteneial and for a CB his passing is amazing (17). He is also cheaper than the other two, less than £10M