First off, yes, you lose TRIM support for the SSD if you include it in a RAID configuration, but no, you don't lose it just because you have other drives in RAID. So you don't have to worry about that.
As to the idea of putting your 1TB Samsung and 500GB WD into RAID 0 - I think it's a very bad idea. If either drive in a RAID 0 volume fails, you lose EVERYTHING on the volume. Not half the files. Everything. That's because half of each file is on each drive, and so is half of the file system. You have already had one scare with this 500GB drive - I would think that depending on it not to fail is not a good idea.
I suggest you use the 500GB and 1TB as separate volumes, and copy files between them.
BTW: in some (most?) RAID controllers, two drives in a RAID 0 configuration have to be the same size, or you can only use the size of the smaller of the two drives.