Bangel, Spuffy, Cangel, Xanya, Fresley, Weslah and Tillow ;)

Bangel, Xanya, Tillow, Funn, Weslah & CorDoyle.

Angel/Cordelia, Buffy/Spike, Willow/Xander, Fred/Gunn, Wesley/Lilah

Well I love most BtVS and AtS couples... but I'd probably go with:
Buffy/Angel, Spike/Drusilla, Willow/Tara (but I have a hard time choosing between Willow & Tara and Willow & Oz), Cordelia/Xander, and Fred/Wesley.

But Xander & Anya and Cordelia & Doyle are also two of my favorite couples, so it's hard to choose. Also love Giles & Jenny. Wesley & Lilah were pretty entertaining as well.

Bangel, Willow &Oz, Tillow, Xanya, Fresley, Cangel (only in Angel), Sprusilla, Cordy & Doyle and Giles & Jenny.

Buffy/Angel, Buffy/Angelus, Willow/Oz, Spike/Drusilla, Cordelia/Xander, Cordelia/Doyle

Bangel, Xanya, Tillow, Funn, Weslah & CorDoyle.

Spike/Buffy, Willow/Oz, Willow/Tara, Cordelia/Xander, Fred/Wesley

Buffy/Angel, Buffy/Spike, Xander/Anya, Xander/Cordelia, Willow/Oz, Willow/Tara, Giles/Jenny, Spike/Drusilla, Angel/Cordelia, Fred/Wesley, Fred/Gunn, Cordelia/Doyle