The Way to Tashahhud (Hadith No. 797)


Volume 1, Book 12, Number 797:
Narrated 'Abdullah:
When we prayed with the Prophet we used to say, "Peace be on Allah from His slaves and peace be on so and so." The Prophet said, "Don't say As-Salam be on Allah, for He Himself is As-Salam, but say, 'At-tahiyatu lil-lahi was-salawatu wat-taiyibatu. As-salamu 'Alaika aiyuhan-Nabiyu warahmatu-l-lahi wa barakatuhu. As-salamu 'alaina wa 'ala ibadillahis-salihin. (If you say this then it will be for all the slaves in heaven or between heaven and earth). Ashhadu an la-ilaha illallahu wa ashhadu anna Muhammadan 'Abduhu wa Rasuluhu.' Then select the invocation you like best and recite it." 

(See Hadith No. 794795 & 796).

P.S. you don't have to select one du`a. You can recite as many as you want.  When you sit for Tashahhud, recite the first du`a, which is mandatory: at-tahiyyatu lillahi...

After that comes the Durud: Allahumma salli `alaa muhammadin...

And after that, select the invocation you like best and recite it. There are a lot of options to choose from. Bring variety to your Salah. :)