What can be done with Delphi

1) Interesting web page with links to resources, programs and  tools associated with Delphi, I recommend you to take a look because it's worth it.

http://okolovich.info/development/delphi/

Among the topics covered are:

Official Embarcadero Documentation
Documentation
Documentation – Firemonkey
Documentation – Reference guide
Documentation – Learning
My Tags
IDE
IDE – Extensions
Source
Libraries
Libraries – Threading
Library – Algorithms
Libraries – Web/Network
Libraries – Script
Libraries – Graphics
Libraries – Crypt
Libraries – DB
Libraries – PDF
Libraries – Messaging
Components
Components – VCL
Components – UI
Components – Web



2) Applications developed and international companies currently working with Delphi


http://delphi.wikia.com/wiki/Good_Quality_Applications_Built_With_Delphi


3) Other utilities:


Delphi matrix library

Delphi image processing

The new image processing library adds a few small but nice features to the mrMath mathematical library. It includes a simple conversion routine from and (to Delphi's TPicture known) input graphic format and coverts it from RGB to either gray scale images or RGB planes in the mrMath's mtirx format/class (and vice verse) 
Based on that format the library implements a few nice image transformation algorithms e.g. to allow warping images. There can be chosen by either a simploe triangulation warping method or one more sphisticated method based on Thin Plate Splines which generally creates smoother warping results but needs more computational power. Note that there exists an 32bit assembler implementation of the warping method based on triangles which makes it lightning fast! 
As a neat add on there is Delauny triangulation class and a class fro procustres analysis which is helpfully to determine the global affine transformation properties from one point cloud to another. 
To get a feeling of the libraries capabilities check out the attached unit test project which nicely shows most of the implemented features.