My nephews are studying at Vasant Vihar (State Board) and we find the school reasonably good.
Singhania (ICSE) at Phokran Road is also good. Admissions for Jr. KG and Sr. KG is by lottery (though they have special quota for JK Singhania Group employees and siblings) The admissions forms are online and results are also provided online. No need to visit the school for admissions at al!
Billabong High (ICSE) is a new school, Infrastructure wise its good but no idea on their staff and teachers. The fees of course are too high.
Little Tigers Playgroup & Nursuray is good option for pre-school.
CBSE and ICSE websites help you identify their affiliated and registed schools in every State and City. Please do check online.
Singhania School: http://www.singhaniaschool.org/
I have noticed that most schools charge too much (other than tution fee) for School Dress, Transportation, Extra activities - Dance, Drama, Computer Lab, Food etc. So consider these extras also if you want to know the actual costs.