Do Muslims meditate or do you consider prayer as a form of meditation? Also, when you pray, do you ever just talk to Allah as if He were walking by your side in the garden or are Muslim prayers liturgical/prescribed similar to Catholics?
Self-control and focus are vital to the prayer as well as leaving behind the worldly life, so, in a sense, there is some meditative practice and benefit in the prayer. However, rather than it being an internal practice only, we are facing and speaking to Allah. As well, though we do not see or hear Allah, we know that he responds back, for example, to each ayah of al-Fatihah (each verse of the opening chapter of al-Qur'an) which we recite in every cycle of the prayer. This is why it is very important that we pay attention to what we are saying and really focus with body, mind, and heart, rather than mindlessly reciting. As well, it is encouraged to make supplications that are purely from the heart or according to our personal needs or concerns in addition to the prescribed words, especially during prostration, which is when we are closest to Allah.
As for imagining ourselves walking in a garden with God, then we do wish to be close and personal with Allah, but not really in this way. Allah is above being compared to or being in His creation, and we cannot locate him in a place or envision Him as a human (or similar being) who would walk next to us. At the same time, Allah says He is closer to us than our own jugular veins (see al-Qur'an 50:16); yet we do not explain how this is, leaving that to Allah's knowledge. What I can say along those lines with regard to my personal experience is that it is amazing to realize that Allah knows exactly my condition and what is in my mind and my heart. He knows my concerns and thoughts completely. Especially because He is the Creator, the Sustainer, and the Controller of all things, this is a healing and stabilizing realization. Regardless of my situation in this life, I can rest in my trust in Allah. This is true for everyone, and the prayer can make a person really conscious of this.