He de o Tengo que

[BobRitter]

He de hablar con tu. I need to speak to you.
Tengo que hablar con tu.

"Tengo que" seems better to me and I have never seen "He de" used.

The conjugation table at:
http://users.ipfw.edu/jehle/COURSES/verbs/haber_verboaux.htm
for the auxilliary form of HABER HAS:
3. There are two main uses for this verb:
a. It is used with the past participle of other verbs to form the compound tenses, otherwise known as the "perfect tenses".
b. It is sometimes used with the preposition de plus and infinitive to mean "to have to" or "to be supposed to".

Thanks.

[Rusty]

Tengo que hablar contigo.

'Tener que' is much more common, but both are used.

[BobRitter]

Gracias Rusty. Pensaba así. Y gracias por el contigo.

[chileno]

He de hablar contigo, is a bit old... but it is correct.