Southern Ocean at Nelson, Victoria
Just a few kilometers from the South Australia border, this is about as far west as you can get in Victoria. According to greatoceanroad.org, Nelson is the western gateway to the Great Ocean Road region (Geelong is the eastern). The Southern Ocean is a stunning blue, helped in no small part by the amazing blue skies over Australia. If you headed south from here, your next stop would be Antarctica.
This is Ocean Beach, and is considered dangerous for swimmers. It's a fairly good-sized beach, so I'll try to give you some perspective on the scale. Look where the beach just disappears behind the foreground brush, toward the upper left of the shot (about 1/3 in and 1/3 down). Now move a little to the right along the water's edge and you'll see a small black object at the waterline. This is a couple who're walking with their black lab (who is a minuscule black dot a bit to the right of the couple).
For those of you who might follow the route with Google Earth, I was standing at 38°03′59.80″S, 141°00′49.13″E (Google Maps) and looking a bit south of east while taking this shot. I've added Google Maps links, but it's just not Google Earth.
If I had a 4WD vehicle, I would've stopped at a couple of spots just east of here. Both appear to be accessible from Quarry Road off the main drag (Portland Nelson Road). The first is at 38°06′58.29″S, 141°07′52.10″E (Google Maps) and the other is at 38°07′45.21″S, 141°10′56.70″E (Google Maps). If the second area, which is at Lake Monibeong (Google Earth incorrectly labels it Lake Bung Bung), is not accessible from Quarry Road, drive further east on Portland Nelson Road and take Bong Bong Road (Google Earth calls it, again, incorrectly, Lake Mombeong Road). These roads are officially Vehicle Tracks (a step below Unsealed Roads), and are 4WD-Only.
Another recommendation I would make, which I unfortunately missed, is to visit Princess Margaret Rose Cave. The tourist literature calls it the "jewel in the crown" of the Lower Glenelg National Park. It's located a handful of kilometers nearly due north of here, at approximately 37°59′18.35″S, 140°59′26.55″E (Google Maps).