With a new campaign, throwing a couple hundred keywords out there and seeing what sticks. Will words that have no impressions, or are out of the budget adversly affect the campaign if you leave them in there?
Words with no impressions will have no discernable impact on your campaign, but words with impressions but no clicks will. The budget is set at campaign level - running out of budget will not negatively impact your campaign, though if it happens regularly, you should probably reduce your bids - that way your advert will run all day, and you'll get more clicks for your money (allowing you to establish what works more quickly).
Its also good to remove any inactive keywords. It helps the account work better. Especially for large account with thousand of keywords.