Any decent IDE would support that, besides this question is already asked before.
So, according to your requierments, I can recommend:
1.Eclipse PDT - Really good, I'm currently using it with XDebug.
2.Netbeans - It was my favorite till I failed to install a Debugger on it. then switched to PDT
these two IDE's provides code completion, syntax checking, and integration with debuggers.
Also, both of them are cross-platform, which means if you ever wanted to return to Windows, they'll be there for you.
Still not intrested?
take a look here