I don't know about best, but I bought a 120GB Kingston A400 for my XP machine.
It makes bootup really fast!
But because Windows XP doesn't support the correct NTFS formatting you are going to need for SSDs, you should first connect it to a Windows 7 or newer PC and use that PC to format the drive as NTFS. Connecting it to this Win7/newer PC can be done by connecting the SSD with internal SATA or with a USB->SATA physical adapter.
There are some Windows XP SSD optimization guides out there, but this page has most of the ones I used:
https://ckirbach.wordpress.com/2012/...isk-operation/