2500k you probably mean. That was the popular i5 for Sandy. I just replaced my 2600k with the 4770k (desktop) and my HTPC is on the IVY (3570k)
basically Sandy = 2500k i5 + Z68
Ivy is 3570k i5+ Z77
haswell is 4670k i5 + Z87
At this point socket 1155 is now dead and socket 1150 is the new kid on the block. The next version of CPU's due on refresh will be called Broadwell and also be socket 1150.
Given that budget seems not your trouble (at least not as much as the actual problem of having a reliable machine) I'd say go socket 1150 on Z87 and get the 4670k i5 on special with the $40 off the mobo. I did that with the i7 I just got and I am really happy. It was a drive for me too (1.5 hours)
Asrock Extreme is a good match up for not too much money. I got the extreme 4 and it has Intel LAN
If you replace your RAM get 2400mhz if you can. Haswell responds well to faster DDR, and is designed to run at higher memory frequency. 8GB kit of 2400mhz should work really nice.
BTW- on socket 1150/Z87 the 24p bug is gone. I get one frame lost every 11 days
given your frustration with your situation- I think a 1150 machine is a worthy and worthwhile upgrade for you.