Veigar got buffed in the last patch....cd on matter reduced by 1 sec and ult damage increased at lower lvls. More importantly the void stone was added giving him some much needed counter to MR. I've been going Mana stone --> tear --> mercury's tread --> void stone. My masteries go up to the magic pen and ignite one in the offensive tree and the rest in utility. The magic pen mastery and void stone are all you need so i dont see the use in getting sorceror's or abyssal anymore.

Early game is still rough without runes, but I get teleport/mana pots to help with mana problems.

Veigar is OP now, at least in my hands. I just went 43/7/6, averageing 18/2. My build personally is Chalice/Philo but mostly chalice, sorc boots, senjais, Void, Abbysal, zhonyas. Basicaly 650 AP and rapes any magic resistance to below starting. My build is 9/0/21 when i hit 30, the magic pen one is best. Even if you have 200 (unlikely) it reduces you to 180-->81-->66. Still a bit, but taking away around 140 withought giving any ground for AP stuff is pretty sick. The only thing that can really beat veigar at this point IMO is a kassidin (basicaly counters everything veigar does), or him being on a bad team.

The new item probably helped a bit, but his other buff is quite negligible damage-wise. His deadliest spell has always been his stun in my opinion. His other spells might kill a person, but a well placed stun wreaks team.