Usage: Personal use really, mainly just a project that will probably just end up running a LAMP server but still aiming for decently high specs so lets just pretend this is to run several game servers or some sort of performance-heavy applications.
Did a bit of research on raid setups and controllers, and I figured RAID 10 should fit me well. I know hard drives are currently inflated in price over the flood but have been coming down lately. What would be an ideal raid card for 4 Hard Drives@ 7200 rpm (may go higher if it's worth it). Was also debating on having an SSD strictly for the OS.
An SSD for the OS plus a RAID is a good choice. If you're spending money on a high-priced RAID card, though, RAID5 is probably a better choice. When you're shopping for RAID cards your first concern should be Linux support.
It is my understanding that theoretically RAID5 is a little faster in write and RAID10 is a little faster in read (it's possible that I have those backwards), but those differences are pretty small with recent hardware and it's about a wash.
When you're dealing with a relatively small array, the advantage of RAID5 is a higher capacity. Four 1TB drives in RAID10 will have a 2TB capacity and four 1TB drives in RAID5 will have a 3TB capacity (assuming no hot spare, which you shouldn't use anyway). Both configurations can withstand a single drive failure. RAID10 can sometimes withstand a second drive failure depending on which drive fails.
There's an arguments for both so it's up to you, but if it were me I would go with RAID5.