Ideally: by dropping the idea of starting with C altogether. Very bad choice!

Better start by reading the following short article by Peter Norvig (director of research at Google):

"Tech yourself programming in 10 years" ( http://norvig.com/21-days.html )

The title is a satirical reference to all those "Teach yourself X programming in Y days" books/tutorials. He explains why such promises are just empty marketing slogans, and gives very reasonable arguments for choosing which language to learn first.

x86 assembler (but before SSE2...), mips assembler, some sparc-assembler, basic, pascal, c, c++, java, perl, python, rudimentary visual basic, bash, haskell.

Damn, forgot about VHDL and Delphi, although I used them in my diploma thesis

pascal

I learned various coding languages in high school. Don't remember most of it though.

Z80, 6502, 65816, 68000, MIPS, x86, ARM7, PS2 VU, and probably more I'm forgetting.

I still love C and assembly. Not fond of needing 30 GB RAM and a 10 core CPU for things we did 20 years ago on a 68000 just because of a Java VM...

SNES mode 7 ftw:

lda #$00
pha
pld
lda #$07
sta $2105

PS2 was probably my favorite system to program on.  I wrote a partial OpenGL miniport fully utilizing chained DMA, VIF/GIF, and VU1 for transforms.  Keeping everything running concurrently and avoiding dependency stalls and the 64 bit dual scalar/vector instruction pair architecture of the VU was just fun as hell. I spent days in color coded Excel cells pipelining the hell out of my VU transform loop around the 7 cycle scalar perspective divide.

When you start out just getting a screen space triangle on the screen sending things directly to GIF, then completely redo the code to send untransformed data to VIF instead, and have a VU program transform, clip, and perspective divide in pipelined VU code and build a GIF packet in VU RAM and xgkick it and get the same triangle on your screen for that very first time, it's orgasm inducing.

Then there was that 4-5 parallax layer demo I did on NES using MMC3 1k CHR ROM bankswitching and scanline IRQ counters.

Heres the zipped ROM in .nes format.  Will run on any NES emulator or on real hardware with a flash cart like a Powerpak that properly implements MMC3.

http://forums.nesdev.com/download/file.php?id=69

As Soleron said, it is easy to learn new programming languages, if you understood basics of programming.

 But out of curiosity I recounted it: Java, C, Pascal, C++, Basic, Assembler, Groovy, Javascript. I don't usually count HTML and such stuff as programming language (more special purpose languages), but as OP counted it: (X)HTML, SQL, LaTeX, XML, Make. I may have forgotten some or the other, doesn't matter much.

And as someone mentioned Stackoverflow: 18K points.

C++ and C#

I guess I could add Java, x86(8086) assemby, html, and matlab to that very short list, but I forgot them.

Yeah, you're actually right html aint programming technically, but potatoe, potaato lol

Including those that I haven't used for a long time:
A little Basic
A little more Z80 Assembler
Pascal
Fortran 77
Modula-2
C
C++

After passing the exams of propedeutic courses, I almost exclusively used C and C++

If scripting languages count then I'll throw those in as well.

HTML (learned in 7th grade)
HTML5
XML
CSS
XHTML
SQL
PL/SQL
Javascript
VB.NET
ASP.NET
C++ (though I'm terribly rusty)
C#
PeopleCode
SQR
COBOL (just enough to understand it)
Java