The Lisbon Treaty will give Europe more democracy, more capacity to decide and act and more international prominence. 

It will give national parliaments control over the European Commission. The commission will not be able to act in areas not expressly set out in the treaties - for example, hunting or even the size of bird cages!
The people will get the chance to petition, to oblige the commission to scrap a decision. The European Parliament, the only institution directly elected by the people, will gain more power - in 40 new areas, for example the Common Agricultural Policy, the EU budget. It will have the power to elect the president of the European Commission.
The treaty will improve efficiency. The new voting rules will take account of the weight of the different member states. So the UK, France and Germany will have greater voting rights in the European Council, where ministers make decisions.
A bill will require the support of 55% of the member states, representing at least 65% of the European population.
The so-called "majority rule" for Council decisions will be extended to more areas. That means quicker decisions and fewer blockages. 

With the Lisbon Treaty, the European people will for the first time be able to challenge the power of European institutions.
National parliaments will be able to challenge decisions that are the prerogative of member
states. Under Lisbon, if one-third of the national parliaments agree on something, they can act together to oblige the Commission to cancel and review a wrong decision. They will also be able to refer the matter to the European Court of Justice.
Parliaments are legally entitled to ratify treaties and international conventions - there is no particular need for national referendums on European issues. Those who ask for referendums want to vote against the EU and their own government.
Referendums are really populist procedures. People use them to answer different questions - not the actual referendum questions.
Did Tony Blair ask by referendum to be allowed to send troops into Iraq? Did Margaret Thatcher ask by referendum to be allowed to carry out social reforms? Did Winston Churchill ask the English people to engage his country against Hitler? No. They all went to parliament, to have a debate and make the best decision. That is also what Sarkozy, Brown and Merkel did.
This treaty is not a constitution. It neither sets up a new constitutional order nor a supranational state. It only brings in new procedures, to improve the decision-making process. These innovations are needed to act better at the European level. 

Link to the full text
http://news.bbc.co.uk/1/hi/world/europe/7927742.stm