The motherboard should have nothing to do with the size of the Harddrive you choose. You could get a 400Gb one or a 1GB one. It's all up to you. The size is limited rather by the operating system.
Actually after you install Windows XP service pack 1, the size limit might still depend on your BIOS. Here's a quoted explaination:
"48-bit Logical Block Addressing (LBA) is a technology which extends the capacity of IDE ATA/ATAPI devices beyond a previous limit of 137.4 GB. This limit applies to IDE ATA/ATAPI devices only and not to SCSI interface devices.
The original design specification for the ATA interface only provided 28-bits with which to address the devices. This meant that a hard disk could only have a maximum of 268,435,456 sectors of 512 bytes of data thus limiting the ATA interface to a maximum of 137.4 gigabytes. With 48-bit addressing the limit is 144 petabytes (144,000,000 gigabytes).
Bottom Line, if your motherboard doesn't have a BIOS with 48-bit LBA addressing abilities, then a BIOS update may need to be implemented.