Seeking developer-friendly web GIS?

Fortunately for you (and all of us!), there are plenty of available (and mature!) options in the FOSS4G world!

Following your technology preferences here's some examples:

• Python
  • Mapfish (not updated since 2011)
  • GeoDjango
• PHP
  • PMapper
• pure Javascript
  • OpenLayers
  • LeafLet
  • OpenLayers + ExtJS
  • OpenLayers + Jquery Mapquery, jeobrowser

For a more complete reference please visit OSGeo.org. It's an umbrella organization for the most popular FOSS geospatial projects out there.

Maybe if you're in the neighborhood you can visit the annual FOSS4G conference. Here's a list of workshops that happened in 2011 regarding web mapping technologies:

• MapFish in Production
• Introduction to Geomajas
• The Moose is loose, Mapping with GeoMoose
• OpenLayers Application Development
• Web Mapping with GeoServer
• Developing OGC Compliant Web Applications With GeoExt
• Interactive space-time dynamics: A hands-on introduction to i2maps
• A complete open source web mapping stack
• There's JavaScript in your backend: Front to Back JavaScript with NodeJS and Polymaps

As for my personal experience developing web mapping applications based on pure javascript/html/css frameworks (OpenLayers/jQuery) can be really straightforward.

If you are interested in Open Source projects, you'll find the answers to this question helpful: What are the FOSS equivalents to these ArcGIS products?

There are quite a lot of different options how to build an OS web mapping stack. Without knowing your use case it's a little difficult to suggest one over the other.

I use GeoServer and connect to an Oracle Database (plugin required for geoserver) this happens to be old Geomedia Datastore that was reprojected into a better coordinate system.

Then use Openlayers to be the map interface of that data (data is pulled from Geoserver by WMS (Web Mapping Service)

Good documentation for this is

http://workshops.opengeo.org/stack-intro/openlayers.html

(you have greater control on this and can customise it as much as as you wish so.)