You don't need the HIDs at all, they will work perfectly well with normal halogen bulbs
If you want all bulbs to match, then replace them all with the same make/model bulb. For instance, all of my bulbs on the front (excluding my LED sidelights) are MTEC Cosmos Blue bulbs, so they all match and have a lovely white light to them, a lot 'whiter' but less bright/light than Osram Nightbreakers