I'll assume that you will switch to WinXP SP3, 32bit version, and that the partitions will be NTFS. The maximum size a disk can have there is not so limited (It is theoretically limited at 2^32-1 clusters, which with a default cluster size of 4Kb would be ~16TB, and with a 64Kb cluster size would be ~256TB). 48bit LBA addressing is enabled by default (since XP SP1), so the 137GB barrier does not exist anymore. If you would need >256TB partitions, you will either have to further increase the cluster size, to switch to a 64-bit OS, to make dynamic disks, or to format the disks using GPT instead of MBR (which will also require switching to a 64-bit OS, either Vista SP1, Server 2008 or Win7, -not XP-, since there is no 32bit support for GPT, and maybe a hardware upgrade if yours doesn't support EFI). Keep in mind that we are talking about partitions here, the actual disks can be of a greater size, but you'd have to make more than 1 partition to be able to access the entire storage capacity. These would be the limits NTFS enforces. But... the NTFS with a MBR ("the usual NTFS") has other limits enforced by the MBR: since MBR relies on the BIOS and the BIOS relies on technology from the era of the i8088 microprocessor (that is "a long long time ago"), the limits MBR has are much lower than 256TB or even 16TB - more precisely, exactly 2TiB (2 * 2^40 bytes) which is a little bit more than 2TB (2*10^12 bytes), the size of your disks. So, your 2TB disks will work fine.
tl;dr version: You'd have no problems with 3 2TB drives under WinXP SP1 or greater.