Even though two-handed weapons don't permit you to equip a shield, some can still be useful in their own way. I'll make a suggestion here: If you want THE two-handed sword, try the Osafune Katana. That thing rocks! Well, here's the list:

Name: Namakura
Description: Poorly made sword
ATT: -5
What it does: Just a crummy two-handed sword.

Name: Muramasa
Description: Bloodthirsty sword
ATT: -3
What it does: Automatically puts Alucard in "Dark Metamorphesis".

Name: Red Rust
Description: Rusty red sword
ATT: -2
What it does: Not a lot, but half the time Alucard tries to draw the sword, it gets stuck in the scabbard, and he grunts with the effort of trying to get it out.

Name: Takemitsu
Description: Bamboo sword
ATT: +1
What it does: Just a lousy two-handed sword.

Name: Nunchaku
Description: Strikes enemy twice
ATT: +10
What it does: Alucard just swings these things twice, once for each hand.

Name: Claymore
Description: Scotch two-handed sword
ATT: +26
What it does: When the combo B-F+ATT is entered, Alucard thrusts forward with the sword.

Name: Sword of Dawn
Description: Summons Dawn warriors
ATT: +27
What it does: When he combo D-DF-F+ATT is entered, Alucard summons the spirit or spirits of ancient warriors, who attack for him.

Name: Flamberge
Description: Flame-edged sword
ATT: +31
What it does: When the combo B-F+ATT is entered, Alucard thrusts with the sword.

Name: Yasutsuna
Description: Yasutsuna-made katana
ATT: +32
DEF: -20
What it does: Just that "flurry of slashes" thing.

Name: Katana
Description: Unsigned katana
ATT: +32
What it does: When the combo D-DF-F+ATT is entered, Alucard swings the sword in a flurry of slashes that can hardley be seen.

Name: Great Sword
Description: Greatsword of Aubec
ATT: +37
What it does: Nothing, just a 2-handed sword.

Name: Zwei Hander
Description: German two-handed sword
ATT: +38
What it does: When the combo B-F+ATT is entered, Alucard thrusts with the sword.

Name: Estoc
Description: German thrust sword
ATT: +39
What it does: Alucard doesn't swing this sword, he thrusts forward with it.

Name: Obsidian Sword
Description: Two-handed obsidian sword
ATT: +42
What it does: When the combo B-F+ATT is entered, Alucard thrusts with the sword.

Name: Osafune Katana
Description: Osafune-made katana
ATT: +50
DEF: -10
What it does: This is a cool sword! When the combo B-F+ATT is entered, Al makes a flurry of quick slashes. When the combo D-DF-F+ATT is entered, he first dashes torward, then does the quick slashes (similar to the Alucard Sword).

Name: Masamune
Description: Legendary Masamune katana
ATT: +62
DEF: -30
What it does: Yes, this is the same kind of sword Sephiroth has! When Al just plain swings it, it creates that "flurry of slashes" effect. When the combo D-DF-F+ATT is entered, Alucard darts forward, does these blindingly fast slashes, then darts back to where he was.