Although haven't had time to make a card (with work, life and all) I do work with both traditional drawing and digital mediums for my job. Personally I think like digital cards are jsut as good at handcrafted cards. But like handcrafted cards, the quality of digital cards depends on the materials used and understanding of the programs you use to make it.
If you want to go digital I find photoshop is one of the best programs out there for photo manipulation, painting...well everything really.
One thing i think that jsut makes working digitally easy and fun is a graphics tablet. Once you get one you'll never want to use a mouse again.
You get great control with one of these things. Unlike a mouse these things (depending on model) has pressure sensitivity, allowing you great control over shading, line thickness, and such and such. I use a wacom introus 3. this is a professional model. the wacom grafires are student ones. both are good (although i love my introus 3) but are abit pricey.
if you're not serious about digital work, you can still get a cheap graphics tablet out there that does the same thing, but of course not as good.
there are many programs you can use. Painter is a good program to use if for drawing/painting if you want a traditional medium feel. It replicates the effect of traditional mediums effectively without the mess.
Illustrator is a vector program. It's good if your not so good at drawing, as you can go in and edit the points manually to get the shape you want. Although personally i perfer using flash (also a vector program used for animation) this is just because i work with this program more at work, and its a hassle running to programs at onces that do similar things. (HOWEVER illustrator has far more functions).
there are alot of sites that have tutorials for digital painting and photo manipulation. I'm not at my computer now so I don't have access to my bookmarks.
but if you want some inspiration these sites are some of my favorites off the top of my head.www.nivbed.com
(this site has some nice links)www.gfxartist.com www.cgtalk.com
this one has a forum full of advice on all sorts of digtal programs. (mind you there can be alot of jargon involved)
Wow ok that was a long post.