Speech Browser Component Recommendations

Hello,

I am currently learning VoiceXML as part of an undergraduate 
project to build a VoiceXML speech browser.  Does anyone have 
any recommendations on what I should use to provide the 
components of the speech browser?  I am currently considering:

VoiceXML Interpreter: OpenVXI
Text-to-Speech Engine: IBM ViaVoice TTS SDK (Windows)
Speech Recognition Engine: IBM ViaVoice SDK (Windows)
Telephony Platform: Vovida SIP stack

but if anyone has used other packages before and found them 
satisfactory, I would appreciate your recommendations.

Thank you.

Jeffrey Wei