You also need to be careful about which powers you take - to make sure that you can use most (if not all) of them whether you're two-handing or working the range.
You also get somewhat shafted on ability scores - to remain effective at higher levels, you need to keep boosting both Strength and Dexterity, which means you can't boost Wisdom - and that means you get less benefit from all the +Wisdom powers.
IMO, the multi-purpose ranger is going to be better off at lower levels than at higher levels.
Once you hit Paragon, especially, you have to pick which route you're focusing on more.
There will be some specialization even at the low levels - you need to pick which build option you will be using. Generally speaking, I think that most people will pick the TWF option over the archery option for a multi-purpose ranger. This will tend to mean that you're not going to be quite so specialized for archery, because you can't take the archery specific paragon paths.
As for at wills - well, Twin Strike is the obvious choice, and the second one is more of a toss-up between Hit and Run and Nimble Strike, depending on how you're going to play - if you're human (which is worth considering for the feat), you get all three.
For encounters and dailies - your to-hits will either be unequal or you'll be getting less benefit from +Wisdom powers. This means either you will be looking for as many attacks as possible (especially when using the lower ability) to increase your likelyhood of putting out damage or you'll want to consider powers that aren't +Wisdom.
But above all, at higher levels, you'll be a resource sink to maintain high combat efficacy - you'll either be using thrown weapons that aren't as good for ranged work, or you'll be needing at least 3 weapons (or one ranged weapon and a double weapon) that are level appropriate.
In essence, you wind up needing to get more of the party resources allocated to you, have one or more weapons fall behind in level, skimp on armor or other non-weapon items, and/or decide to retrain and specialize a tad bit more.
Of course, if you do want to do this, you should talk with your DM about some of the issues, and hopefully the DM will be kind and adjust Treasure finds accordingly - say instead of just one shiny new melee weapon for the ranger to play with, a linked pair - both have to be wielded/held/worn/possessed by the same person to get the full benefit of their powers, otherwise, they are lower level weapons or otherwise not as good as when the same person uses both of them. And, of course, attempting to recycle one, but not both, would be a Bad Idea, and merchants wouldn't want to buy only part of a pair.