Probably none. At 2 years old, even if your kid has an off the charts IQ, the cognitive areas of the brain simply haven't developed enough for any game console, educational or otherwise, to be of any real use. It could, in fact, be a hindrance to mental development.
For about the first 5 or so years, one of the best things you can do, is spend time talking to your child. Get a bunch of children's books and read them to him. This will pay serious dividends when it comes to his language skill development later in life. Study after study shows that the more parents talk to their kids, the better they tend to do later in life academically.
I know it's tempting to just give your kid some kind of device, or sit him down in front of the TV, just so you can have a few minutes to yourself, but at such a young age, you'd be doing your son a great disservice. When he gets to 7-8 you can think about a game console, since by then he can at least cognitively process most of what is going on.
So-called educational toys, like those Leapfrog things, are a crock IMO. By the time they would have any real benefit, the kid is probably too old to have any interest in them. The kid isn't actually learning anything, just responding to stimuli. All they've learned is that if they hit a specific button at a specific time, something good happens.
If you're really interested in your son's mental development, take that money for a game console, and buy children's books. Spend an hour or two a day reading them to your son. You will be absolutely sick of those books by the time you're done, so you just have to keep telling yourself that you're doing this for your son. Then when he's old enough to start reading on his own (which you should encourage, since reading improves spelling, logical thinking skills, grammar, and a host of other useful skills) you can just donate the kid's books to a local library or something. Then, in 5-6 years, you're welcome to come back and ask about game consoles again.
<span id="INSERTION_MARKER"><span id="INSERTION_MARKER">Hi there<span><span>
<span><span>The last couple of weeks I have been struggling trying to choose a game console for my 2-year old boy and cannot come up with a decision.
<span><span>Any pointers in the right direction will be a blessing.
<span><span>Thanks in advance