Two factors to consider...
Factor 1: Your equipment's compatibility ...
If you get a wireless n router, then (if you actually want the faster transmission rate) your computer, laptop, and game system's wireless nic cards (or whatever you use) will need to be capable of receiving the upgraded router transmission. 802.11n is the N router protocol so check the tech specs of computer/laptop/game system to see if they are capable of receiving that protocol.
Chances are HIGH that your computer/laptop/game system are only up to 802.11g (or 802.11b or 802.11a depending on how old they are -- those are the older wireless protocols; g being the current standard one). So in addition to getting a wireless N router, you'd probably need new nic cards for each of your computers as well
Otherwise, you could get the N router, just make sure it is backwards compatible to still transmit to the other protocols that your computers use. You won't get faster speeds though, just a shiny new router.
Factor 2: protocol finalization ...
802.11n (the wireless N protocol) is technically still in "draft" release (if you look at the tech specs for any wireless N router, you'll notice it says "draft 802.11n compatible". I don't think the final version isn't scheduled for release until mid-next year.
No one will be able to 100% guarantee/promise you that a "draft compatible" wireless N router that you purchase now will still work with the final release N protocol... though, it is likely that it will, just not a guarantee.
Since N is seeing a consumer market at this stage, despite the draft protocol it's most likely stable. So it wouldn't be a total gamble if you need something working _now_.
If your needs and income are willing to go for a draft release, then, sure, go for it. Otherwise, I'd say wait until next year (I believe summer 2009) for final release.
