Last night I kicked WoF's butt in a fairly easy battle.

Upgraded my armor to orichalcum, still using my Godly Night's Edge. But I am getting my clock cleaned regularly within spitting distance of home. Wraiths I can generally take down with little to no pain, but about half the time my sword does exactly no damage to other beasties like Possessed Armors and Werewolves. Got the Obsidian Shield, so I know its not just that knockback is causing the misses.

Is this just the way things are? The easiest hardmode beasties are tougher than pre-hardmode bosses? Or do I need special weapons? I've tried the Molten Bow with Hellfire Arrows, that Chakra thingie, even the Bee Gun, but its getting hard to grow stuff with all the tombstones around.

I don't mind games where your character dies when you do something stupid, but the lethality I'm seeing in early hardmode when I'm not sure I'm doing anything wrong is getting me close to uninstalling. Any suggestions?

Tch. I'm no expert on Terraria but I can very much relate to the frustration in Hardmode. I think I taught myself a few new curse words.

You could join the Company of Cowards (that would be... me) and build a floating fort - just enough lava so that loot doesn't burn. During events and invasions I used to hide there and whimper. It's an easy way out until you can find or craft better weapons/armor.
( and [url=http://terraria.gamepedia.com/Dao_of_Pow]Dao of Pow, Adamantine/Titanium for armor, use Spelunker potions to find the ore. On that note, there's an entire [url=http://terraria.gamepedia.com/Guide:Getting_Started_with_Hardmode]guide[/url] for getting started in Hardmode, if you want to dig through it.)

Maybe look out for accessory upgrades, craft new ones and reforge for defense. (For running away like a little girl, speed would also be appropriate - on that note, wings let you flee upwards!)
It would seem that in the beginning, ranged weapons can keep you alive a little longer. In general you just have to hop around a lot to avoid getting hit, versus standing still and bashing heads in pre-hardmode. (That's what I did anyway.)

Also potions, mainly Regeneration, Ironskin and of course healing.

It... yeah, there is a reason it's called Hardmode. :|
It's quite survivable once you get used to it and equipped though - and I'm not exactly good at games. You should do better than I, too, as I didn't have a "fairly easy battle" against WoF either.

Hardmode needs a bit of preparation, otherwise youl will have a very hard time to find enough ore.
I generally create some kind of grid of tunnels.
The first thing i create in preparation is an at least 4 blocks wide protection trench around my base. The bottom is roughly at zero-level. The left and right sides far enough that the Hardmodebiomes don't affect my base. If i have a corrupt world, i line this trench with bricks or wood, to protect against the growing vines. A four block wide gap cannot be jumped by spreading Hallow or Crimson/Corruption.

I then start to dig tunnels, extending east and west, in a straight line, until whenever i'm getting bored ;) I use platforms and stone to keep that tunnel level, so i can run trough using lightning boots.
Then i start digging additional 2 blocks wide hellevators until just before i reach the lava level. On that level, just high enough that i won't be bothered by the lava, i build another horizontal tunnel.

The upper tunnel will allow you to find altars outside of your corruption/crimson, since these will always spawn at that level. Also, after you spawned the new ores, you can use this tunnel to easily get to it. The lower tunnel and the hellevators enable you to easily get at the better hardmode ores. Also the tunnels will be good areas to farm souls, or enable you to get access to good farming areas without to big a hassle.

This is quite a bit of work, especially on a large world, but it will make the start of harmode a lot easier.

Thanks for the suggestions. I think maybe my problem is server lag.

I activated hardmode in single player last night, and I'm not seeing the same problems. Night's Edge takes them all down easily enough in single player, but when I join the multiplayer, it no longer cuts it. (Sorry for the pun.) Guess I'll have to get a more beefy computer and see if that takes care of it.

By zero level, do you mean by the depth meter, or the default spawn location? If the former, do you clear the background to show sky clear down to there, and all the way across the world (except for oceans and dungeon, of course.)

With zero level, i mean according to the depth meter. The level where the removable dirt background disappears.
And no, i do not remove the background. Sometimes i think i am crazy enough digging these tunnels, time consuming as it is *g*