i just changed to starhub fibre plan..
the lag spikes are seriously very bad..i get very horrible ping when playing d3..
when on cable i was 250-300ping.. now after changing to fibre i get ~300 with lag spikes every 1-2mins which goes up to 800-1k ping.

is there something wrong with the hardware or the isp's problem??
It has to do with your wireless connection. I'm on SH fibre too, D3 America shows green, average 250ms, tops 255ms.
My sis fiber optic always got problem with Mac Lion OSx. SH tech support says the dlink router is to be blamed as it is unable to connect to the router. Any alternatives besides using the dlink router?
I disabled wireless mode for SH Dlink router as my connection keeps dropping once in awhile (mac and pc). I am using wireless home plug las i stay in landed property (3 levels). Total my house have 3 wireless home plug, 1 wired home plug which is ethernet to SH Dlink router. wireless N for whole house is solid.
Take note that i cannot achieve full 100mbps local connection as my wireless home plug rated at 200mpbs, but in actual in my house lowest is 90mbps (furthest away) to 150mbps (nearest), factoring in wireless mode it again decreases speeds, but not so significant as its wireless N.
download/upload speed local is about speed test: 30mbps down, 30mbps up respectively wireless N on my macbook pro lion.
... lastly, SH dlink router is a rip off as its already a known issue that it can't hold wireless connection for long. Called them a few times to complain long ago, but after that i gave up.